SI3484-A01-GM - SILICON LABS - Datasheet.Directory

64-PORT POE POWER MANAGEMENT CONTROLLER

Features

Applications

Description

The Si3484 is a power manager intended for use with the Si3459 Power over

Ethernet (PoE) Power Sourcing Equipment (PSE) controllers for power

management of up to 64 ports with three power sources.

The Si3459 is capable of delivering over 30 W per port, which means that, in a 24-

or 48-port system, a very large power supply would have to be used to avoid

overload. Typically, not all ports are used at full power; so, a smaller power supply

can be used along with the Si3484 power management controller.

Use of the Si3484 power manager greatly simplifies system implementation of

power management. The Si3484 power management controller is programmed

via a SPI or UART interface to set the system power supply capacity, the port

power configuration (Type 1: 15.4 W, or high-power Type 2: 3 0 W) ports, the port

priority, the detection timing (Alternative A or Alternative B), and the fault recovery

protocol. Once programmed, the configuration data can be saved, and the Si3484

can work without host intervention. Port and overall status information is available

and continuously updated.

The Si3484 uses the real-time overload and current monitoring capability of the

Si3459 to manage power shared among up to 64 ports. Power management is

selectable between grant-based or consumption-based algorithms in order to

supply power to the greatest number of ports.

In high-reliability systems, multiple power supplies are often connected to provide

redundancy, which further increases the power supply monitoring requirements.

The Si3484 can manage up to three power supplies automatically, enabling or

disabling ports in priority order.

Enables use of smaller power

supplies for up to 64-port PoE

systems with Si3459 and Si3454

PSE Controller ICs

Can operate with or without a host

Configuration save capability

Pin-selectable SPI or UART interface

Pin-selectable UART data rate

Fully-compliant with IEEE 802.3-AT

Types I and II

Supports classification-based and

LLDP power negotiation

Supports individual port priority and

port configuration

Supports Power supply status from

up to 3 power supplies

24-pin Quad flat pack package

4x4 mm PCB footprint; RoHS

complaint

Extended temperature operating

range (–40 to +85 °C)

Power over Ethernet Endpoint

switches and Midspans

Supports high-power PDs, such as:

Pan/Tilt/Zoom security cameras

Wireless Access Points

Security and RFID systems

Industrial automation systems

Networked audio

IP Phone Systems and iPBXs

Pin Assignments

24-Pin QFN

See "5. Pin Descriptions" on page 45.

MISO

SCK

GND

RST

RSVD PSLCT

RSVD

BAUD1

RESET_PSE

RSVD

PS3

PS2

MOSI

NSS

RSVD

SCL

BAUD0

VDD

PS1

SDA

INT

Top View

(Pads on Bottom of Package )

Si3484

2 Rev. 1.0

Functional Block Diagram

PD PD PD PD PD PD PD PD PD PD PD PD

Power S uppl y 1

Power S uppl y 2

Power S uppl y 3

Power Suppl y Pr esent

UART or SPI

Select

UART or SPI

UART

Baud Rate

Power

I2C

Si3484 Application Diagram

MCU or

Host C ont roller

Si8631

Di gital Isolator

Si3484 Power

Management

Controller

PD PD PD PD PD PD PD PD PD PD PD PD

Si 3459 Por t Controller Si 3459 Por t C ont roller Si 3459 Port Cont rol ler

Si3484

Rev. 1.0 3

TABLE OF CONTENTS

Section Page

1. Electrical Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4

2. Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6

2.1. Host Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7

2.2. Hardware Only Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8

3. Serial Packet Protocol . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9

3.1. Packet Format . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .10

3.2. SPP Error Handling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .14

4. Power Manager API . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .15

4.1. System Status . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .18

4.2. Port Status . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .21

4.3. System Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .26

4.4. Port Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .28

4.5. System Configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .30

4.6. Port Configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .36

4.7. Power Supply Status . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .42

4.8. Events . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .43

4.9. Return Codes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .44

5. Pin Descriptions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .45

6. Ordering Guide . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .47

7. Package Outline: 24-Pin QFN . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .48

8. PCB Land Pattern . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .50

9. Top Marking Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .52

Si3484

4 Rev. 1.0

1. Electrical Specifications

Table 1. Recommended Operating Conditions

Description Symbol Test Condition Min Typ Max Unit

Operating Temperature

Range TANo airflow –40 — 85 °C

VDD Supply Voltage VDD All operating modes 2.7 — 3.6 V

Table 2. Absolute Maximum Ratings

Parameter Test Condition Min Typ Max Unit

Ambient Temperature

under Bias –55 — 125 °C

Storage Temperature –65 — 150 °C

Voltage on any I/O with

Respect to GND VDD>2.2 V –0.3 — 5.8 V

Voltage on VDD with

Respect to GND –0.3 — 4.2 V

Note: S tresses above those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. This is a

stress rating only and functional operation of the devices at those or any other conditions above those indicated in the

operation listings of this specification is not implied. Exposure to maximum rating conditions for extended periods may

affect device reliability.

Table 3. Electrical Characteristics

Parameter Symbol Test Condition Min Typ Max Unit

Input High VIH Input pins:

RST, SCK, MOSI, NSS,

RX, PSn, BAUDn,

SLCTIN, SCL, SDA

2.0 — — V

Input Low VIL ——0.8V

Input Leakag e Curr en t IIL ——±1uA

Output Low

(MOSI, TX, SCL, and SDA) VOL IOL =8.5mA — — 0.6 V

Output High

(MOSI, TX) VOH IOH =–3mA V

DD–0.7 — — V

VDD Current IDD VDD = 3.0 V*

VDD = 3.6 V* ——8.6

12.1 mA

*Note: VDD = 2.7 to 3.6 V, –40 to 85 °C unless otherwise noted.

Si3484

Rev. 1.0 5

Figure 1. SPI Timing Diagram

Figure 2. UART Timing Diagram

Table 4. Timing Requirements

Parameter Symbol Min Max Unit

SPI Timing Require m ents (See Figure 1)

NSS Falling to First SCK Edge TSE 84 — ns

Last SCK Edge to NSS Rising TSD 84 — ns

NSS Falling to MISO Valid TSEZ —168ns

NSS Rising to MISO High Z TSDZ —168ns

SCK High Time TCKH 210 — ns

SCK Low Time TCKL 210 — ns

MOSI Valid to SCK Sample Edge TSIS 84 — ns

SCK Sample Edge to MOSI Change TSIH 84 — ns

SCK Shift Edge to MISO Change TSCH —168ns

Maximum SPI Clock Speed FMAX —1MHz

UART Requirements (See Figure 2)

Deviation of Tx Transmit Speed from Pin-programmed Value ∆FTx –3 +3 %

Deviation of Rx receive Speed from Pin-programmed Value ∆FRx –4 +4 %

MSB Bit 4Bit 5Bit 6 Bit 1Bit 3 Bit 2 Bit 0

NSS

MISO

MOSI

SCK

TSE

TSEZ

TCKH TCKL

TSCH

TSIS

TSIH

TSD

TSDZ

D1D0 D2 D3 D4 D5 D6 D7

START

BIT

MARK STOP

BIT

BIT TIMES

BIT SAMPLING

SPACE

Si3484

6 Rev. 1.0

2. Functional Description

The Si3484 Power Management Controller takes the role of the central controller in a Silicon Labs Power over

Ethernet (PoE) system. In a PoE system, power is provided by one or more power supplies and is consumed by

one or more powered devices (PDs). The Si3484 decides which of the PDs can have power and monitors the

amount of power co nsumed by each.

A host microcontroller unit (MCU) can configure the Si3484 and can query the status of the PDs and the power

supplies. The Si3484 stores it s configu ration in internal flash memo ry. A host MCU uses a Universal Asynchronous

Receiver Transmitter (UART) or a Serial Peripheral Interface (SPI) to communicate with the Si3484. Pins on the

Si3484 select which host interface to use and which baud rate to use for the UART interface.

Power supplies may be inserted into bays. The Si3484 supports a system with up to three bays. Power supplies

may be inserted or removed from the bays at any time. Each bay provides a signal to the Si3484 that indicates if a

power supply is present and operational in the bay. The outputs of the power supplies are ganged together to

provide a single po we r sou r ce fo r the s yst em .

The Si3484 manages a collection of Si3459 Port Controllers. The Si3484 supports a system with up to 8 Si3459s.

Each Si3459 has eight ports; so, a system may have up to 64 ports. The Si3459 performs low-level port functions,

such as detecting and classifying PDs. The Si3484 has a global view of the system and manages power across all

ports.

PDs are connected to ports on the Si3459s. PDs may be connected or disconnected from the ports at any time.

When a PD is connected to a port, then the PD requests power from the port. The Si3484 determines the amount

of power requested from the classification of the PD. If there is enough power remaining, the Si3484 grants the

request; otherwise, the Si3484 denies the request.

The host may configure an optional power limit for each port. A power limit restricts the amount of power that the

Si3484 grants to a port. If a power request is greater than the power limit, the Si3484 does not fully grant the

request, but only grants the amount of the power limit.

The Si3484 supports Link Layer Discovery Protocol (LLDP) agents in the ho st. An LLDP agent ca n call a ro utine in

the Si3484 to dyna mi ca lly adjust the am o un t of power granted to a PD during the course of a connection.

Several PDs may be connected to a PoE system. The Si3484 may have granted different amounts of power to

each PD, and each PD may be consuming different amounts of power. If a PD consumes more power than it is

granted (port overload), the Si3484 turns off the PD.

There are two approaches that the Si3484 can take when granting requests for power. The granting policy can be

grant-based or it can be consumption-based.

Figure 3. Powered Devices Example

Si3484

Rev. 1.0 7

Figure 4. Grant Based Power Management

Figure 5. Consumption-Based Power Management

If the granting policy is grant based, then the power remaining for new grants is the total ungranted power. The

power remaining is the total power provided minus the total power granted.

The problem with this approach is that much of the provided power is unused because PDs often do not consume

all of their granted power.

If the granting policy is consumption-based, then the power remaining for new grants is the total unconsumed

power. The power remaining is the total power provided minus the total power consumed (excluding the reserved

power). This approach uses more of the provided power, but there is a possibility that the system may consume

more power than the power provided (system overload).

To avoid system overloads caused by momentary surges in power consum ption, th e host can spe cify that a ce rtain

amount of power be held in reserve. The Si3484 does not use the reserved power when granting new requests.

Most power supplies can tolerate a limited amount of overload for a short duration. The host specifies the overload

limit of the power supplies to the Si3484. If a system overload is less than the overload limit, the Si3484 turns off

ports, one at a time in priority order, until the system is no longer overloaded. If a system overload is greater than

the overload limit (severe overload), the Si3484 immediately turns off all low-priority ports. If the system is still

overloaded, the Si3484 turns off additional ports, one at a time in priority order, until the system is no longer

overloaded. A severe overload is usually caused by removing a power supply.

2.1. Host Interface

The Si3484 has a UART interface and an SPI interface for communicating with the host MCU, but only one

interface is used at a time. The PSLCT (protocol select) pin selects which interface is used.

2.1.1. UART Interface

If the PSLCT pin is tied high, then the Si3484 uses the UART interface to communicate with the host MCU. The

Si3484 uses the TX and RX pins to send and receive se rial data. The BAUD0 and BAUD1 pins select the baud rate

for the UART interface.

Si3484

8 Rev. 1.0

The UART interface uses eight data bits, no parity, and one stop bit.

2.1.2. SPI Interface

If the PSLCT pin is tied low, then the Si3484 uses the SPI interface to communicate with the host MCU. The

Si3484 is an SPI slave device. Therefore, it receives data on the MOSI pin and sends data on the MISO pin. The

host MCU drives the NSS and SCK pins.

The SPI interface uses an active-high clock (CKPOL = 0). The clock line is low in the idle state, and the leading

edge of the clock goes from low to high. The SPI interface samples the data on the leading edge of the clock

(CKPHA = 0). The SPI interface transfers the most-significant bit first, and the maximum bit rate is 1 Mbps.

2.2. Hardware Only Mode

The host interface (SPI or UART) and the UART baud rate are pin-configured. The Si3484 reads the pin

configuration at power up, and it cannot be changed after power up. The hardware designer only needs to decide

which interface to use and, if UART is selected, which BAUD rate to use.

In general, the host interface must be electrically isolated from the host MCU using an appropriate electrical

isolator for either SPI or UART signals as well as power supply status signals as needed.

The Si3484 backs up its configuration to internal flash memory. Once the Si3484 is configured, it is possible to

disconnect the host interface and use the Si3484 without a host MCU.

Table 5. Baud Rates

BAUD1 BAUD0 Baud Rate (bps)

L L 19200

L H 38400

H L 57600

H H 115200

Si3484

Rev. 1.0 9

3. Serial Packet Protocol

The Si3484 contains the Power Manager component and the interface to the Power Manager is a collection of

routines known as the Power Manager application programming interfa ce (API).

The Power Manager API is described later in this manual. The host MCU should contain a Serial Packet Client,

which calls the routines in the Power Manager API to get status information and configure and control the Power

Manager.

The Serial packet protocol (SPP) is a remote proced ure call (RPC) mechanism that allows a Serial Packet client to

call routines in the Power Mana ger. The Serial Packet Protocol is implemented by a Serial Packet Client in the host

MCU and the Serial Packet Server in the Si3484. The Serial Packet Client should be implemented by the user in

the host MCU. Silicon Labs has reference code available; please contact Silicon Labs for further information.

The Serial Packet Server receives a packet from a Serial Packet Client and then calls the specified routine in the

Power Manager. When the Power Manager routine returns, the Serial Packet Server sends a packet back to the

Serial Packet Client.

Figure 6. Serial Packet Protocol

PSE Controller Support

S i3459 or S i3454

I2C

P ower Manager

Serial Packet Server

Si3484

QueriesReplies S erial P acket P rotocol

(Rem ot e P rocedure Call)

UART or SPI

S erial Packet Client

Ho st C on t ro ll er F i rmw are

Host MCU

Si3484

10 Rev. 1.0

3.1. Packet Format

A packet is a sequence of fields sent together as a unit. Figure 7 shows the SPP packet format.

Figure 7. Packet Format

Each field is a single byte except for the Data field. The Data field length may be from zero to 255 bytes.

3.1.1. Start Field

The Start field marks the beginning of a packet and always contains the Start-of-Packet (SOP) character (0xAC). If

data is lost on the host interface, the Serial Packet Server and the Serial Packet Client use the Start field to

resynchronize. A “receive packet” routine starts by re ceivin g and discardin g bytes until the SOP char acter is foun d.

3.1.2. Checksum Field

The Checksum field is used to verify that the p acket was not co rrupted durin g transmission. The sender o f a p acket

calculates the checksum and writes it into the Checksum field. The receiver of a packet verifies that the checksum

is correct. The Checksum field should contain the value such that all the bytes in the packet, except for the Start

field, add up to zero.

Figure 8. Packet Checksum

To calculate the checksum, the sender uses an 8-bit variable to sum up the bytes of the Routine field through the

end of the Data field. The sender adds one to the one's complement of this sum and stores the result in the

Checksum field.

To verify the checksum, the receiver uses an 8-bit variable to sum up the bytes of the Routine field through the

Checksum field. The sum should be zero.

3.1.3. Routine Field

The Routine field identifies a routine in the Power Manager API.

The client uses the Routine field to specify which routine to call. The client should verify that the Routine field in a

received packet matches the Routine field in the sent packet. Definitions of routines can be found in “4. Power

Manager API” .

3.1.4. Data Length Field

The Dat aLength field specifies the number of bytes in the Da t a field. Th e number of b ytes may be from zero to 255.

3.1.5. Data Field

The Data field is used to pass data to and from the Si3484. The Data field may contain four different types of data:

Parameters

System Information

Port Information

Events

The Data field has a different format for each type of data. The format of commands issued by the host to the

power manager is fixed, but the format of the returned values may be of four different types: Parameters, System

Information, Port Information, and Events.

To elaborate, in all packets issued by the host, the Data Field has the Parameters format. Most of the returned

packet are also in the Parameters format, the only exceptions being the packets that are received back after calling

Start Routine Data Lengt h Data Checksum

Sum of Bytes is Zero

Checksum ~Sum1+=

Si3484

Rev. 1.0 11

the RTN_GETSYSTEMINFO, RTN_GETPORTINFO, and RTN_GETEVENTS routines. The Data Fields for these

return packets are in the System Information format, Port Information format, and Events format, respectively.

3.1.5.1. Parameters Format

The Parameters format of the Dat a fiel d is used to p ass p arameters to Power Manager routines. In most cases, the

Parameters format is also used to return data from the routines.

Figure 9. Parameters Format

The Parameters format has an 8-bit Parm8 field followed by a 32-bit Parm32 field (see Table 6). Depending on the

routine being called, Parm8, Parm32, or both fields are used. Sometimes, neither field is used. However, both

fields are always sent and received. The DataLength field contains five.

Table 6. Use of Parameters

Routine Parameters in Query Packet Parameters in Reply Pack et

Parm8 Parm32* Parm8 Parm32*

Get System Status SystemStatus

Get System Info Uses System Information Format

Get Total Power Consumed PowerConsumed

Get Total Power Granted PowerGranted

Get Total Power Provided PowerProvided

Get Port Count PortCount

Get Port Status Port PortStatus

Get Port Info Port Uses Port Information Format

Get Port Priority Status Port PortPrioritySta tus

Get Port Power Consumed Port PowerConsumed

Get Port Power Granted Port PowerGranted

Get Port Power Requested Port PowerRequested

Get Port Power Available Port PowerAvailable

Reset System Result

Restore Fact or y Def au l ts

Store Configuration

Set Port Control Port Control Result

Adjust Port Power Port PortPower Result

Set Power Provided PowerSupply PowerProvided Result

*Note: The Parm32 field is big endian; therefore, the most significant byte is first.

Start Routine Data Length Data Checksum

Parm8 Parm32

Si3484

12 Rev. 1.0

Get Power Provided PowerSupply PowerProvided

Set Reserved Power ReservedPower Result

Get Reserved Power ReservedPower

Set Overload Limit OverloadLimit Result

Get Overload Limit OverloadLimit

Set Granting Policy GrantingPolicy Result

Get Granting Policy GrantingPolicy

Set Retry Policy RetryPolicy Result

Get Retry Policy RetryPolicy

Set Port Enable Port Enable Result

Get Port Enable Port Enable

Set Port Capability Port Capability Result

Get Port Capability Port Capability

Set Port Midspan Port Location Result

Get Port Midspan Port Location

Set Port Priority Port Priority Result

Get Port Priority Port Priority

Set Port Legacy Support Port Legacy Result

Get Port Legacy Support Port Legacy

Set Port Power Limit Port PowerLimit Result

Get Port Power Limit Port PowerLimit

Get Power Supply Status PowerSup p ly Status

Get Events Uses Events Format

Get System Time System Time in ms

Set Power Inflation Power Inflation

Get Power Inflation Power Inflation

Set Soft Start Policy Soft Start Policy

Get Soft Start Policy Soft Start Policy

Table 6. Use of Parameters (Continued)

Routine Parameters in Query Packet Parameters in Reply Pack et

Parm8 Parm32* Parm8 Parm32*

*Note: The Parm32 field is big endian; therefore, the most significant byte is first.

Si3484

Rev. 1.0 13

3.1.5.2. System Information Format

The System Information format of the Data field is used to return system information to the client. System

information is returned after calling the RTN_GETSYSTEMINFO routine.

Figure 10. System Information Format

The System Information format has a Powe rManager Version field followed by a PlatformSuppor tVersion field. Both

of these fields are eight bytes long and contain a version string that is a zero-terminated ASCII string. A version

string may be from one to seven characters long. The Routine field contains RTN_GETSYSTEMINFO, and the

DataLength field contains 16.

3.1.5.3. Port Information Format

The Port Information format of the Data field is used to return port information to the client. Port information is

returned after calling the RTN_GETPORTINFO routine.

Figure 11. Port Information Format

The Port Information format is a sequence of fie lds as sh own abov e. For mo re information, read the description of

the RTN_GETPORTINFO routine in the Power Manager API Section. The Routine field contains

RTN_GETPORTINFO, and the DataLeng th fie ld co ntains 17.

The Result field contains the return code from the RTN_GETPORTINFO routine, and, if Result is not SUCCESS

(0), the remaining fields should be ignored.

The Current and PowerSupplyVoltage fields are big endian. Therefore, the most significant byte comes first.

3.1.5.4. Events Format

The Events format of the Data field is used to return events to the client. Events are returned after calling the

RTN_GETEVENTS routine.

Figure 12. Events Format

In the Si3484, the Serial Packet Server internally receives events from the Power Manager and stores them in a

circular event queue. If the event queue becomes full, newer events overwrite older events.

If a client wishes to receive events, it should periodically get the events from the Serial Packet Server. The client

gets the events by sending a packet with the Routine field set to RTN_GETEVENTS. The Serial Packet Server

returns all the events from the event queue in a single packet with the Data field in the Events format.

Start Routine Data Length Data Checksum

PowerManagerVersion PlatformSupportVersion

Start Routine Data Length Data Checksum

Result Detection Classification Current Power Supply

Voltage Silicon

Version Firmware

Version

Start Routine Data Length Data Checksum

Event ...

Event Event Event

Parm1Type Parm2

Si3484

14 Rev. 1.0

The Data field does not have a fixed length. The length of the Data field depends on the number of events that are

returned. An event is three bytes long; so, the number of events in the Data field is DataLength divided by three. If

there are no event s to return, then Dat aLength is zero, and the Dat a field is empty. The maximum nu mber of event s

that can be returned is 72.

3.1.6. Serial Packet Format s

All four packet formats must use th e same “Parameters” packet format when the host issue a transfer even if the

return format is System Info, Port Info or Event.

3.2. SPP Error Handling

There are many reason s why a client may not receive ba ck a p acket. Pe rhap s the Si3484 is not r unning or perhap s

the serial data was corrupted or lost during transmission (in either direction). In any case, it is not prudent for a

Serial Packet Client to call a serial receive routine that blocks forever until data is received. If the serial receive

routine does not have a timeout option, the client should not call the receive routine unless it knows that received

data is available . If a clie nt doe s not receive a packet within one second of se nd ing a packet, then the client should

assume that there has been a co mmunications e rror. The client should resend th e original packet or simply give up

(but do not wait forever to receive a packet).

When the Serial Packet Server receives a packet, it validates the packet. If the checksum is bad or the Routine

field is invalid, the Serial Packet Se rver ignor es the p acket and do es not sen d back a p a cket in resp onse. Af ter one

second, the client should realize that a packet has not been received and should resend the original packet.

The Si3484 checks the configuration every 30 seconds to see if it has changed. If the configuration has changed,

the Si3484 backs up the configuration to internal flash memory. While the Si3484 is writing to flash memory, it

cannot send or rece ive packet s on the host interface. If a host MCU sends a packet to the Si3 484 while it is backing

up the configu ration, the packet is lost. If a host MCU does not receive a packet back within one second, the host

MCU should resend the original packet.

Si3484

Rev. 1.0 15

4. Power Manager API

User Interface components call the routines in the Power Manager API to get status information and configure and

control the Power Manager. The Power Manager API has routines for:

Management

System Status

Port Status

System Control

Port Control

System Configuration

Port Configuration

Power Supply Status

Events

Output packet format is ‘Param eters Format’ in all cases. Input packet format depends on the routine .

Maximum of the ‘Port’ parameter of the routines (where applicable) is 64 ports, but only ports available in the

system g ive a valid result.

Some functions can emit error codes. De scr iptions of the er ror cod es can be found in "4.9. Return Cod es" on page

Values in the “Symbol” column of the tables are recommended names for constant values.

To build a valid query packet, the user must specify the routine and provide the necessary parameters. If the

parameter is indicate d as “None ”, the serial packet server does not rely on the passed value, so the recommended

value is 0. In case of receiving reply packets, the parameters indicated as “None” should be ignored by the host.

The serial packet server will echo back the routine name in the reply packet, which can be used along with the

checksum value to check for consistency.

Table 7 contains routines available through the serial packet protocol.

Table 7. Power Manager Routines

Routine Value Symbol

Get System Status 1 RTN_GETSYSTEMSTATUS

Get System Info 2 RTN_GETSYSTEMINFO

Get Total Power Consumed 3 RTN_GETTOTALPOWERCONSUMED

Get Total Power Granted 4 RTN_GETTOTALPOWERGRANTED

Get Total Power Provided 5 RTN_GETTOTALPOWERPROVIDED

Get Port Count 6 RTN_GETPORTCOUNT

Get Port Status 7 RTN_GETPORTSTATUS

Get Port Info 8 RTN_GETPORTINFO

Get Port Priority Status 9 RTN_GETPORTPRIORITYSTATUS

Get Port Power Consumed 10 RTN_GETPORTPOWERCONSUMED

Get Port Power Granted 11 RTN_GETPORTPOWERGRANTED

Get Port Power Requested 12 RTN_GETPORTPOWERREQUESTED

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16 Rev. 1.0

Get Port Power Available 13 RTN_GETPORTPOWERAVAILABLE

Reset System 14 RTN_RESETSYSTEM

Restore Fact or y Def au l ts 15 RTN_RESTOREFACTORYDEFAULTS

Set Port Control 16 RTN_SETPORTCONTROL

Adjust Port Power 17 RTN_ADJUSTPORTPOWER

Set Power Provided 18 RTN_SETPOWERPROVIDED

Get Power Provided 19 RTN_GETPOWERPROVIDED

Set Reserved Power 20 RTN_SETRESERVEDPOWER

Get Reserved Power 21 RTN_GETRESERVEDPOWER

Set Overload Limit 22 RTN_SETOVERLOADLIMIT

Get Overload Limit 23 RTN_GETOVERLOADLIMIT

Set Granting Policy 24 RTN_SETGRANTINGPOLICY

Get Granting Policy 25 RTN_GETGRANTINGPOLICY

Set Retry Policy 26 RTN_SETRETRYPOLICY

Get Retry Policy 27 RTN_GETRETRYPOLICY

Set Port Enable 28 RTN_SETPORTENABLE

Get Port Enable 29 RTN_GETPORTENABLE

Set Port Capability 30 RTN_SETPORTCAPABILITY

Get Port Capability 31 RTN_GETPORTCAPABILITY

Set Port Midspan 32 RTN_SETPORTMIDSPAN

Get Port Midspan 33 RTN_GETPORTMIDSPAN

Set Port Priority 34 RTN_SETPORTPRIORITY

Get Port Priority 35 RTN_GETPORTPRIORITY

Set Port Legacy Support 36 RTN_SETPORTLEGACYSUPPORT

Get Port Legacy Support 37 RTN_GETPORTLEGACYSUPPORT

Set Port Power Limit 38 RTN_SETPORTPOWERLIMIT

Get Port Power Limit 39 RTN_GETPORTPOWERLIMIT

Set Power Supply Status 40 RTN_SETPOWERSUPPLYSTATUS

Get Power Supply Status 41 RTN_GETPOWERSUPPLYSTATUS

Table 7. Power Manager Routines (Continued)

Routine Value Symbol

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Get Events 42 RTN_GETEVENTS

Store Configuration 43 RTN_STORECONFIG

Set Soft Start Policy 45 RTN_SETSOFTSTARTPOLICY

Get Soft Start Policy 46 RTN_GETSOFTSTARTPOLICY

Get System Time 47 RTN_GETSYSTEMTIME

Set Power Inflation 48 RTN_SETPOWERINFLATION

Get Power Inflation 49 RTN_GETPOWERINFLATION

Table 7. Power Manager Routines (Continued)

Routine Value Symbol

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18 Rev. 1.0

4.1. System Status

The System Status routines allow a User Interface component to get the following information:

System Status

System Info

Total Power Consumed

Total Power Granted

Total Power Provided

4.1.1. Get System Status

Get the status of the system.

Routine:

RTN_GETSYSTEMSTATUS

Query data:

Parm8: None

Parm32: None

Reply packet format:

Parameters

Reply data:

Parm8: System status

Parm32: None

The system status is the overall status of the system. A negative system status value is an error that is not specific

to a particular port.

Table 8. System Status Values

Status Value Symbol

OK 0 STATUS_SYSTEM_OK

Initialization Failed –1 STATUS_SYSTEM_INIT_FAIL

Under Voltage –2 STATUS_SYSTEM_UNDER_VOLT

Over Temperature –3 STATUS_SYSTEM_OVER_TEMP

Communications Lost –4 STATUS_SYSTEM_COMM_LOST

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4.1.2. Get System Info

Get information about the system.

Routine:

RTN_GETSYSTEMINFO

Query data:

Parm8: None

Parm32: None

Reply packet format:

System Information

Reply data:

Bytes 0..7 Power Manager Version (zero-terminated string)

Bytes 8..15 Platform Support Version (zero-terminated string)

Return strings contain the version of the Power Manager and the version of the Platform Support component as

zero-termin a te d str ing s.

4.1.3. Get Total Power Consumed

Get the power consumed by all PDs.

Routine:

RTN_GETTOTALPOWERCONSUMED

Query data:

Parm8: None

Parm32: None

Reply packet format:

Parameters

Reply data:

Parm8: None

Parm32: Total power consumed in mW

4.1.4. Get Total Power Granted

Get the power granted to all PDs.

Routine:

RTN_GETTOTALPOWERGRANTED

Query data:

Parm8: None

Parm32: None

Reply packet format:

Parameters

Reply data:

Parm8: None

Parm32: Total power granted in mW

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20 Rev. 1.0

4.1.5. Get Total Power Provided

Get the power provided by all power supplies

Routine:

RTN_GETTOTALPOWERPROVIDED

Query data:

Parm8: None

Parm32: None

Reply packet format:

Parameters

Reply data:

Parm8: None

Parm32: Total power provided in mW

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4.2. Port Status

The Port Status routines allow a User Interface component to get the following information:

Port Count

Port Status

Port Info

Port Priority Status

Port Power Consumed

Port Power Granted

Port Power Requested

Port Power Available

4.2.1. Get Port Count

Get the number of ports in the system.

Routine:

RTN_GETPORTCOUNT

Query data:

Parm8: None

Parm32: None

Reply packet format:

Parameters

Reply data:

Parm8: Number of ports in the system

Parm32: None

When the Power Manager st art s up, it discovers the number o f ports in the syste m by searching for port controllers.

4.2.2. Get Port Status

Get the status of a port.

Routine:

RTN_GETPORTSTATUS

Query data:

Parm8: Port number

Parm32: None

Reply packet format:

Parameters

Reply data:

Parm8: Port status value or an error code

Parm32: None

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22 Rev. 1.0

If a port is blocked, then the PD consume d more po wer than it was granted (port overload), and the retry policy is

“retry af ter reconnect” . To remove the block, the user must physically disconnect the PD fr om the port. Anothe r way

to remove the block is to disa b le an d th en re- en a ble the por t.

4.2.3. Get Port Info

Get low-level port information.

Routine:

RTN_GETPORTINFO

Query data:

Parm8: Port number

Parm32: None

Reply packet format:

Port Information

Reply data:

Byte 0: Result

Byte 1: Detection value (see table 11.)

Byte 2: Classification value (see table 12.)

Byte 3..4: Port current in mA, 16bit, MSB first

Byte 5..6: Power supply voltage in mV, 16bit, MSB first

Byte 7..8: PSE silicon version

Byte 9..14: PSE firmware version

Table 9. Port Status Values

Status Value Symbol Description

Disabled 0 STATUS_PORT_DISABLED The port is off because it is not allowed to turn

on.

Powered On 1 STATUS_PORT_POWERED_ON A PD is connected and receiving power.

Powered Off 2 STATUS_PORT_POWERED_OFF The port is off because a PD is not connected.

Denied 3 STATUS_PORT_DENIED The port is off be cause there is not enough

power remaining to grant the p ower request.

Blocked 4 STATUS_PORT_BLOCKED The port is off because of a port overload.

Forced On 5 STATUS_PORT_FORCED_ON The user forced the port on.

Forced Off 6 STATUS_PORT_FORCED_OFF The user forced the port off.

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4.2.4. Get Port Priority Status

Get the priority status of a port.

Routine:

RTN_GETPORTPRIORITYSTATUS

Query data:

Parm8: Port number

Parm32: None

Reply packet format:

Parameters

Reply data:

Parm8: Port priority status

Parm32: None

Table 10. Detect Values

Detection Result Value Symbol

Unknown 0 DETECT_UNKNOWN

Short 1 DETECT_SHORT

Low 3 DETECT_LOW

Good 4 DETECT_GOOD

High 5 DETECT_HIGH

Open 6 DETECT_OPEN

Table 11. Classification Values

Classification Result Value Symbol

Unknown 0 CLASS_UNKNOWN

Class 1 1 CLASS_1

Class 2 2 CLASS_2

Class 3 3 CLASS_3

Class 4 4 CLASS_4

Unequal fingers 5 CLASS_UNEQ_FINGERS

Class 0 6 CLASS_0

Overload 7 CLASS_OVERLOAD

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24 Rev. 1.0

The priority status of a port is the currently-active priority and may be different than the configured priority of the

port. If a port is forced on or off and the configured priority is low or high, the priority status is elevated to the fo rced

priority. If a forced port is returned to automatic control, the Power Manager returns the priority status to the

configured priority.

4.2.5. Get Port Power Consumed

Get the power that a PD is currently using.

Routine:

RTN_GETPORTPOWERCONSUMED

Query data:

Parm8: Port

Parm32: None

Reply packet format:

Parameters

Reply data:

Parm8: None

Parm32: Port power consumed in mW or an error code

4.2.6. Get Port Power Granted

Get the power that is allocated to a PD.

Routine:

RTN_GETPORTPOWERGRANTED

Query data:

Parm8: Port

Parm32: None

Reply packet format:

Parameters

Reply data:

Parm8: None

Parm32: Port power granted in mW or an error code

Table 12. Port Priority Status Values

Status Value Symbol

Low 0 PRIORITY_LOW

High 1 PROIRITY_HIGH

Forced 2 PRIORITY_FORCED

Critical 3 PRIORITY_CRITICAL

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4.2.7. Get Port Power Requested

Get the power that is requested by a PD.

Routine:

RTN_GETPORTPOWERREQUESTED

Query data:

Parm8: Port

Parm32: None

Reply packet format:

Parameters

Reply data:

Parm8: None

Parm32: Port power requested in mW or an error code

4.2.8. Get Port Power Available

Get the power that is available for a PD.

Routine:

RTN_GETPORTPOWERAVAILABLE

Query data:

Parm8: Port

Parm32: None

Reply packet format:

Parameters

Reply data:

Parm8: None

Parm32: Port power available in mW or an error code

An LLDP agent calls this routine to determine maximum power that the power manager can provide for a port. If a

port has a power limit, th en th e power limit is r eturned. If a port does not h ave a p ower limit and the por t can sup ply

high power, then 40 W (maximum power) is returned; otherwise, 15.4 W (low power) is returned.

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26 Rev. 1.0

4.3. System Control

The System Control routines allow a User Interface component to:

Reset the system

Restore factory default settings

Store the configuration immediately in the non-volatile memory

Retrieve the system’s internal time

4.3.1. Reset System

Reset the system.

Routine:

RTN_RESETSYSTEM

Query data:

Parm8: None

Parm32: None

Reply packet format:

Parameters

Reply data:

Parm8: Result. Zero (for success) or an error code

Parm32: None

4.3.2. Restore Factory Default

Restore the configuration to factory default values.

Routine:

RTN_RESTOREFACTORYDEFAULTS

Query data:

Parm8: None

Parm32: None

Reply packet format:

Parameters

Reply data:

Parm8: None

Parm32: None

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Rev. 1.0 27

4.3.3. Store Configuration

Store the configuration immediately in the non-volatile memory.

Routine:

RTN_STORECONFIG

Query data:

Parm8: None

Parm32: None

Reply packet format:

Parameters

Reply data:

Parm8: None

Parm32:None

4.3.4. Get System Time

Return the system time in milliseconds since system restart.

Routine:

RTN_GETSYSTEMTIME

Query data:

Parm8: None

Parm32: None

Reply packet format:

Parameters

Reply data:

Parm8: None

Parm32: The time in milliseconds since system restart.

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28 Rev. 1.0

4.4. Port Control

The Port Control routines allow a User Interface component to:

Set port control

Adjust port power

4.4.1. Set Port Control

Controls the method of port turn on and off

Routine:

RTN_SETPORTCONTROL

Query data:

Parm8: Port number

Parm32: Control

Reply packet format:

Parameters

Reply data:

Parm8: Zero (for success) or an error code

Parm32: None

If the port control is automatic, the Power Manager automatically turns the port on and off when a PD is connected

and disconnected from the port. If the port control is forced on, the port's priority is boosted to the forced priority

level. This usually results in the port turning on. However, a forced port cannot cause a critical priority port to turn

off in order to turn on the forced port. If a forced port is granted power, the Power Manager turns on a forced port

even if no PD is detected. If the port co ntrol is forced of f, the port is unconditionally turned of f and held of f. A forced-

off port is considered to be temporarily off, while a disabled port is considered to be permanently off.

4.4.2.AdjustPortPower

Adjust the power granted to a PD.

Routine:

RTN_ADJUSTPORTPOWER

Query data:

Parm8: Port

Parm32: Requested port power in mW

Reply packet format:

Parameters

Reply data:

Parm8: Zero (for success) or an error code

Parm32: None

Table 13. Control Values

Control Value Symbol

Automatic 0 PORT_CTRL_AUTOMATIC

Force on 1 PORT_CTRL_F ORCE_ON

Force off 2 PORT_CTRL_FOR CE_ OF F

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An LLDP agent calls this routine to reallocate the power granted to a PD. The agent can request more power than

is currently granted or it can request less power than is currently granted. This routine allows an LLDP agent to

dynamically change the amount of power granted to a PD during the course of a connection. A port must be on

before its power can be adjusted.

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30 Rev. 1.0

4.5. System Configuration

The System Configuration routines allow a User Interface component to set and ge t these items:

Power provided

Reserved power

Overload limit

Granting policy

Retry policy

Power inflation

Soft start policy

4.5.1. Set Power Provided

Set the amount of power that is output from a power supply.

Routine:

RTN_SETPOWERPROVIDED

Query data:

Parm8: Power supply (1 to 3)

Parm32: Power provided by the power supply in mW

Reply packet format:

Parameters

Reply data:

Parm8: Zero (for success) or an error code

Parm32: None

4.5.2. Get Power Provided

Get the amount of power that is output from a power supply.

Routine:

RTN_ RTN_GETPOWERPROVIDED

Query data:

Parm8: Power supply (1 to 3)

Parm32: None

Reply packet format:

Parameters

Reply data:

Parm8: None

Parm32: Power provided by the power supply in mW

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Rev. 1.0 31

4.5.3. Set Reserved Power

Set the percentage of power that is reserved from granting.

Routine:

RTN_SETRESERVERPOWER

Query data:

Parm8: Reserved power in percentage of the total power

provided

Parm32: None

Reply packet format:

Parameters

Reply data:

Parm8: Zero (for success) or an error code

Parm32: None

4.5.4. Get Reserved Power

Get the percentage of power that is reserved from granting.

Routine:

RTN_GETRESERVEDPOWER

Query data:

Parm8: None

Parm32: None

Reply packet format:

Parameters

Reply data:

Parm8: Reserved power in percentage of the total power

provided

Parm32: None

If the granting policy is consumption-based, the Power Manager holds this amount of power in reserve. The Power

Manager does not use the reserved power to grant new requests. This creates a power buffer that reduces the

likelihood of system overloads caused by momentary surges in consumption.

4.5.5. Set Overload Limit

Set the maximum system overload that the power supplies can tolerate.

Routine:

RTN_SETOVERLOADLIMIT

Query data:

Parm8: Overload limit as a percentage of the total power

provided

Parm32: None

Reply packet format:

Parameters

Reply data:

Parm8: Zero (for success) or an error code

Parm32: None

Si3484

32 Rev. 1.0

4.5.6. Get Overload Limit

Get the maximum system overload that the power supplies can tolerate.

Routine:

RTN_GETOVERLOADLIMIT

Query data:

Parm8: None

Parm32: None

Reply packet format:

Parameters

Reply data:

Parm8: Overload limit as a percentage of the total power

provided

Parm32: None

The overload limit is the maximum system overload that the power supplies can tolerate. It is expressed as a

percentage of the total power provided. If a system overload is less than the ov er loa d lim it, th e po rts are t ur ne d off

one at a time. If a system overload is greater than the overload limit (severe overload), all of the low-priority ports

are immediate ly tu rn ed off.

4.5.7. Set Granting Policy

Set the granting policy.

Routine:

RTN_SETGRANTINGPOLICY

Query data:

Parm8: Granting policy

Parm32: None

Reply packet format:

Parameters

Reply data:

Parm8: Zero (for success) or an error code

Parm32: None

4.5.8. Get Granting Policy

Get the granting policy.

Routine:

RTN_GETGRANTINGPOLICY

Query data:

Parm8: None

Parm32: None

Reply packet format:

Parameters

Reply data:

Parm8: Granting policy

Parm32: None

Si3484

Rev. 1.0 33

The granting policy is used by the Power Manager when deciding if a request for power should be granted. If the

granting policy is grant based, the remaining power is considered to be the total ungranted power. If the granting

policy is consumption-based, the remaining power is considered to be the total unconsumed power (excluding the

reserved power). If the remaining power is greater than or equal to the requested power, then the Power Manager

grants the reques t.

Grantbased:

PowerRemaining = TotalPowerProvided–TotalPowerGranted

Consumptionbased:

PowerRemaining = TotalPowerProvided–TotalPowerConsumed–ReservedPower

4.5.9. Set Retry Policy

Set the retry policy.

Routine:

RTN_SETRETRYPOLICY

Query data:

Parm8: Retry policy

Parm32: None

Reply packet format:

Parameters

Reply data:

Parm8: Zero (for success) or an error code

Parm32: None

4.5.10. Get Ret r y Pol ic y

Get the retry policy.

Routine:

RTN_GETRETRYPOLICY

Query data:

Parm8: None

Parm32: None

Reply packet format:

Parameters

Reply data:

Parm8: Retry policy

Parm32: None

Table 14. Granting Policy Values

Granting Policy Value Symbol

Grant-based 0 GRANT_POLICY_GRANT_BASED

Consumption-based 1 GRANT_POLICY_CONSUMPTION_BASED

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34 Rev. 1.0

The retry policy specifies when the Power Manager tries again to power a port that is turned off because of a port

overload. A port overload is when the power consumed by a PD is greater than the power granted to that PD. If the

retry policy is “immediate”, the Power Manager tries to turn the port back on immediately. If the retry policy is

“reconnect”, the Power Manager waits until the PD is disconnected and then reconnected before it tries again to

power the port. The Power Man ager m ust detect an open circuit on the por t before retrying. If the retry policy is “re-

enable”, the Power Manager disables the port when a port overload occurs. The user must re-enable the port

before the Power Manager tries to power the port again.

4.5.11. Set Power Inflation

Set the power inflation applied to all ports.

Routine:

RTN_SETPOWERINFLATION

Query data:

Parm8: The power inflation as a percentage of a port’s granted power

Parm32: None

Reply packet format:

Parameters

Reply data:

Parm8: Zero (for success) or an error code

Parm32: None

4.5.12. Get Power Inflat io n

Get the power inflation applied to all ports

Routine:

RTN_GETPOWERINFLATION

Query data:

Parm8: None

Parm32: None

Reply packet format:

Parameters

Reply data:

Parm8: The power inflation as a percentage of a port’s granted power

Parm32: None

Power inflation allows a port to draw a fixed perce ntage more than its granted power. It is a gl obal setting applied to

each port independently. It is a configuration parameter bound be twe e n 0% an d 25 % of gr an te d power.

Table 15. Retry Policy Values

Retry Policy Value Symbol

Immediate 0 RETRY_IMMEDIATELY

Reconnect 1 RETRY_AFTER_RECONNECT

Re-enable 2 RETRY_AFTER_REENABLE

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4.5.13. Set Soft Start Policy

Set the Soft Start Policy for the system

Routine:

RTN_SETSOFTSTARTPOLICY

Query data:

Parm8: Soft start policy

Parm32: None

Reply packet format:

Parameters

Reply data:

Parm8: Zero (for success) or an error code

Parm32: None

4.5.14. Get Sof t Sta r t Pol ic y

Get the power inflation applied to all ports

Routine:

RTN_GETSOFTSTARTPOLICY

Query data:

Parm8: None

Parm32: None

Reply packet format:

Parameters

Reply data:

Parm8: Soft start policy

Parm32: None

Soft start boots the system with 0W total power to avoid unintentional port turn on in a host-controlled environment.

After system boot using soft start, the ho st should call “Set Power Provided” to provide the a ctual supply wattage to

the system.

Table 16. Soft Start Policy Values

Soft Start Policy Value Symbol

Soft start disabled 0 SOFT_START_DISABLED

Soft start enabled 1 SOFT_START_ENABLED

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4.6. Port Configuration

The Port Configuration routines allow a User Interface component to set and get

Port enable

Port capability

Port priority

Port power limit

Power location

4.6.1. Set Port Enable

Set whether a port is enabled to turn on.

Routine:

RTN_SETPORTENABLE

Query data:

Parm8: Port

Parm32: Enable (enable: 1, disable: 0)

Reply packet format:

Parameters

Reply data:

Parm8: Zero (for success) or an error code

Parm32: None

4.6.2. Get Port Enable

Get whether a port is allowed to turn on.

Routine:

RTN_GETPORTENABLE

Query data:

Parm8: Port

Parm32: None

Reply packet format:

Parameters

Reply data:

Parm8: Enable (enabled: 1, disabled: 0) or error code

Parm32: None

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4.6.3. Set Port Capability

Set whether a port can supply high po wer.

Routine:

RTN_SETPORTCAPABILITY

Query data:

Parm8: Port

Parm32: Capability

Reply packet format:

Parameters

Reply data:

Parm8: Zero (for success) or an error code

Parm32: None

4.6.4. Get Port Capability

Get whether a port is allowed to turn on.

Routine:

RTN_GETPORTCAPABILITY

Query data:

Parm8: Port

Parm32: None

Reply packet format:

Parameters

Reply data:

Parm8: Capability or error code

Parm32: None

If the port hardware is designed to supply high power (PoE+), set Capability to one. Otherwise, set Capability to

zero. Note that a port’s capability cannot be changed while the port is on

Table 17. Port Capability Values

Capability Value Symbol

Low power 0 CAPABILITY_LOW_POWER

High power 1 CAPABILITY_HIGH_POWER

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38 Rev. 1.0

4.6.5. Set Port Power Location

Set the location of the power source.

Routine:

RTN_SETPORTPOWERLOCATION

Query data:

Parm8: Port

Parm32: Location

Reply packet format:

Parameters

Reply data:

Parm8: Zero (for success) or an error code

Parm32: None

4.6.6. Get Port Power Location

Get the location of the power source.

Routine:

RTN_GETPORTPOWERLOCATION

Query data:

Parm8: Port

Parm32: None

Reply packet format:

Parameters

Reply data:

Parm8: Location or error code

Parm32: None

If the power source is within an Ethernet switch, the location is “endpoint”. If the power source is inserted between

an Ethernet switch and a PD, the location is “midspan”. The Power Manager uses different back-off timings for

different locations. The Power Manager assumes that an endpoint device uses the Alternative A pinout and that a

midspan device uses the Alternative B pinout. For alternative A, power is applied to wire pairs 1,2 and 3,6. For

alternative B, power is applied to wire pairs 4,5 and 7,8

(the spare pairs in the ca se of 10/100 Ethe rne t). Co nven tionally, alternative B is used for midspan powe r inje ctor s.

For alternative B, detection is done with over 2 seconds between detection pulses so as to avoid interfering with

end-point equipment trying to provide power using alternative A.

Table 18. Power Location Values

Location Value Symbol

Endpoint 0 LOCATION_ENDPOINT

Midspan 1 LOCATION_MIDSPAN

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Rev. 1.0 39

4.6.7. Set Port Priority

Set the priority of a port.

Routine:

RTN_SETPORTPRIORITY

Query data:

Parm8: Port

Parm32: Priority

Reply packet format:

Parameters

Reply data:

Parm8: Zero (for success) or an error code

Parm32: None

4.6.8. Get Port Priority

Get the priority of a port.

Routine:

RTN_GETPORTPRIORITY

Query data:

Parm8: Port

Parm32: None

Reply packet format:

Parameters

Reply data:

Parm8: Priority or error code

Parm32: None

The priority of a port indicates how important it is that the port receives power. If there is not enough power

provided for all ports that want power, then the low priority ports are the first ports to be denied. Critical priority ports

are the last ports to be denie d.

If a port is forced on, then the port's priority is elevated to the forced priority level. Forced priority is between high

priority and critical priority and cannot be directly set by the user. When a port is forced on, it may cause a high

priority port to be turned off, but it can never cause a critical priority port to be turned off.

If a severe overload occurs, all of the low priority ports are immediately powered off.

Table 19. Port Priority Values

Priority Value Symbol

Low 0 PRIORITY_LOW

High 1 PRIORITY_HIGH

Critical 3 PRIORITY_CRITICAL

Si3484

40 Rev. 1.0

4.6.9. Set Port Legacy Support

Enable or disable legacy support.

Routine:

RTN_SETPORTLEGACYSUPPORT

Query data:

Parm8: Port

Parm32: Enable (enable: 1, disable: 0)

Reply packet format:

Parameters

Reply data:

Parm8: Zero (for success) or an error code

Parm32: None

If disabled then only IEEE standard 802.3AF- or AT-compatible PDs will be detected. Otherwise non-standard PDs

with large common-mode capacitance (legacy PDs) will be detected as well.

4.6.10. Get Port Legacy Support

Get the legacy support setting of a port

Routine:

RTN_GETPORTLEGACYSUPPORT

Query data:

Parm8: Port

Parm32: None

Reply packet format:

Parameters

Reply data:

Parm8: Enable (enable: 1, disable: 0) or error code

Parm32: None

If enabled the legacy PDs will be detected.

4.6.11. Set Port Power Limit

Set the power limit of a port.

Routine:

RTN_SETPORTPOWERLIMIT

Query data:

Parm8: Port

Parm32: Limit, maximum power that may be granted to a port

in mW

Reply packet format:

Parameters

Reply data:

Parm8: Zero (for success) or an error code

Parm32: None

Si3484

Rev. 1.0 41

4.6.12. Get Port Power Limit

Get the power limit of a port

Routine:

RTN_GETPORTPOWERLIMIT

Query data:

Parm8: Port

Parm32: None

Reply packet format:

Parameters

Reply data:

Parm8: None

Parm32: Limit, maximum power that may be granted to a port

in mW

Power limit restricts the amount of power that may be granted to a port. If a port's power limit is zero, the Power

Manager grants the power requested without restriction. If a port's power limit is greater than zero, the Power

Manager grants the lesser of the power limit or the power requested. If a power request is greater than the power

limit, the Power Manager grants less power than requested.

Si3484

42 Rev. 1.0

4.7. Power Supply Status

The Power Supply Status routine allows a User Interface component to get:

Power Supply Status

4.7.1. Get Power Supply Status

Get the status of a power supply.

Routine:

RTN_GETPOWERSUPPLYSTATUS

Query data:

Parm8: Port

Parm32: None

Reply packet format:

Parameters

Reply data:

Parm8: Status

Parm32: None

A User Interface co mp o nent calls this fun ctio n to deter min e whet he r a po we r sup p ly is pre sen t in a ba y.

If the voltage on the specified power supply pin (PS1, PS2, or PS3) is high, this routine returns

STATUS_POWER_SUPPL Y_INSER TED, otherwise, this routine returns STATUS_POWER_SUPPLY_REMOVED.

Table 20. Power Supply Status Values

Status Value Symbol

Removed 0 STATUS_POWER_SUPPLY_REMOVED

Inserted 1 STATUS_POWER_SUPPLY_INSERTED

Si3484

Rev. 1.0 43

4.8. Events

The Event routine allows a User Interface component to get:

System events

Port events

Power supply events

Error events

Informational events

4.8.1. Get Events

Get the events from the event queue.

Routine:

RTN_GETEVENTS

Query data:

Parm8: None

Parm32: None

Reply packet format:

Events

Reply data:

This routine retur ns a series of ev en t de scr iptors (maximum 72) which consist of 3 bytes each:

Byte 0: Event type

Byte 1: Parm1, value depends on event type

Byte 2: Parm2, optional, value depends on event type

Parameters Parm1 and Parm2 depend on event type:

System event:

Parm1: value corresponding to System status values (see Table 9.)

Parm2: None

Port event:

Parm1: value corre s ponding to Port status values (see Tabl e 10.)

Parm2: port number

Power supply event:

Parm1: value corresponding to Power supply status values (see Table 20.)

Parm2: power supply number

Error event:

Parm1: value corresponding to System status values (see Table 23.)

Parm2: error specific

Table 21. Event Type Values

Event Type Value Symbol

System 1 EVENT_TYPE_SYTSEM

Port 2 EVENT_TYPE_PORT

Power supply 4 EVENT_TYPE_POWER_SUPPLY

Error 8 EVENT_TYPE_ERROR

Information 16 EVENT_TYPE_INFO

Si3484

44 Rev. 1.0

Informat i on al ev en t:

Parm1: value corresponding to System status values (see Table 2 2.)

Parm2: None

4.9. Return Codes

The routines of the Power Manager API return codes to indicate the success or failure of an operation. These

codes are also use d in Parm 1 of erro r even ts and infor m atio n even ts.

Table 22. Information Code Values

Event Type Value Symbol

Restored to factory defaults 1 INFO_DEFAULTS_RESTORED

System reset 2 INFO_SYSTEM_RESET

Configuration saved 3 INFO_CONFIG_SAVED

Table 23. Return Code Values

Return Code Value Symbol

Success 0 SUCCESS

Port number is invalid –1 ERROR_PORT_INVALID

Power supply number is invalid –2 ERROR_PWR_SUPLY_INVALID

Parameter is invalid –3 ERROR_PARAMETER_INVALID

Cannot create resource –4 ERROR_RESOURCE_CREATE

Resource is invalid –5 ERROR_RESOURCE_INVALID

Cannot configure resource –6 ERROR_RESOURCE_CONFIG

Cannot read from resour ce –7 ERROR_RESOURCE_READ

Cannot write to resource –8 ERROR_RESOURCE_WRITE

Cannot find the resource –9 ERROR_RESOURCE_NOT_FND

Cannot load the configuration –10 ERROR_CONFIG_LOAD

Cannot save the configuration –11 ERROR_CONFIG_SAVE

Configuration data is invalid –12 ERROR_CONFIG_INVALID

Configuration data is corrupt –13 ERROR_CONFIG_CORRUPT

System overload –14 ERROR_SYSTEM_OVERLOAD

Port overload –15 ERROR_PORT_OVERLOAD

Startup overload –16 ERROR_STARTUP_OVERLOAD

Si3484

Rev. 1.0 45

5. Pin Descriptions

Table 24. Si3484 Pin Descriptions

Pin # Name Type Description

1MISOOutput

SPI output.

2 SCK Input SPI clock.

3 GND Power Ground.

4 VDD Power VDD.

5 RST Input Reset (a low will reset the Si3484).

6 RSVD Reserved Do not connect.

7 RESET_PSE Output Reset output for connection to reset input pins of Si345 9 or Si3454

PSE controllers.

8 RSVD Reserved Do not connect.

9 RSVD Reserved Do not connect.

10 PS3 Input Logic high indicates the power supply is available.

11 PS2 Input Logic high indicates the power supply is available.

12 PS1 Input Logic high indicates the power supply is available.

13 PSLCT Input Tie low to select SPI interface. Tie high to select UART interface.

14 RSVD Reserved Do not connect.

15 BAUD1 Input Tie high or low to select UART baud rate.

MISO

SCK

GND

RST

RSVD PSLCT

RSVD

BAUD1

RESET_PSE

RSVD

PS3

PS2

MOSI

NSS

RSVD

SCL

BAUD0

VDD

PS1

SDA

INT

Top View

(Pads on Bottom of Package )

Si3484

46 Rev. 1.0

16 BAUD0 Input Tie high or low to select UART baud rate.

17 SCL Open Collector Connect to Si3459 SCL and pull up resistor.

18 SDA Open Collector Connect to Si3459 SDA and pull up resistor.

19 INT Input Connect to Si3459 INT and pull up resistor.

20 RSVD Reserved Do not connect.

21 RX Input UART receive.

22 TX Output UART transmit.

23 NSS Input SPI select.

24 MOSI Input SPI input.

Table 24. Si3484 Pin Descriptions (Continued)

Pin # Name Type Description

Si3484

Rev. 1.0 47

6. Ordering Guide

Table 25. Si3484 Ordering Guide

Ordering Part Number Description Package Information

Si3484-A01-GM Powe r management controller 24-pin 4x4 mm QFN

RoHS compliant

Notes:

1. Add “R” to the part number to denote tape and reel option (Si3484-A01-GMR).

2. The ordering part number is not the same as the device mark. See "7. Package Outline: 24-Pin QFN" on page 48 for

device marking information.

Si3484

48 Rev. 1.0

7. Package Outline: 24-Pin QFN

The Si3484 is pa ckaged in an industry-standard, RoHS-compliant 4x4 mm2, 24-pin QFN package.

Figure 13. 24-Pin QFN Mechanical Diagram

Si3484

Rev. 1.0 49

Table 26. QFN-24 Package Dimensions

Dimension Min Nom Max

A 0.70 0.75 0.80

A1 0.00 0.02 0.05

b 0.18 0.25 0.30

D4.00 BSC

D2 2.55 2.70 2.80

e0.50 BSC

E4.00 BSC

E2 2.55 2.70 2.80

L 0.30 0.40 0.50

L1 0.00 — 0.15

aaa — — 0.15

bbb — — 0.10

ddd — — 0.05

eee — — 0.08

Z — 0.24 —

Y — 0.18 —

Notes:

1. All dimensions shown are in millimeters (mm) unl ess otherwise noted.

2. Dimensioning and Tolerancing per ANSI Y14.5M-1994.

3. This drawing conforms to the JEDEC Solid State Outline MO-220,

variation WGGD except for custom features D2, E2, Z, Y, and L which are

toleranced per supplier designation.

4. Recommended card reflow profile is per the JEDEC/IPC J-STD-020

specification for Small Body Components.

Si3484

50 Rev. 1.0

8. PCB Land Pattern

Figure 14. Typical QFN-24 PCB Land Pattern

Si3484

Rev. 1.0 51

Table 27. QFN-24 PCB Land Pattern Dimensions

Dimension MIN MAX

C1 3.90 4.00

C2 3.90 4.00

E 0.50 BSC

X1 0.20 0.30

X2 2.70 2.80

Y1 0.65 0.75

Y2 2.70 2.80

Notes:

General

1. All dimensions shown are in millimeters (mm) unle ss otherwise noted.

2. This land pattern design is based on the IPC-7351 guidelines.

Solder Mask Design

3. All metal pads are to be non-solder mask defined (NSMD). Clearance

between the solder mask and the metal pad is to be 60mm minimum,

all the way around the pad.

Stencil Design

4. A st ainless steel, laser-cut and electro-polished stencil with trapezoidal

walls should be used to assure good solder paste release.

5. The stencil thickness should be 0.125mm (5 mils).

6. The ratio of stencil aperture to land pad size should be 1:1 for all

perimeter pads.

7. A 2x2 array of 1.10mm x 1.10mm openings on 1.30mm pitch should

be used for the center ground pad.

Card Assembly

8. A No-Clean, Type-3 solder paste is recommended.

9. The recommended card reflow profile is per the JEDEC/IPC J-STD-

020 specification for Small Body Components.

Si3484

52 Rev. 1.0

9. Top Marking Diagram

Figure 15. Top Marking Diagram

Table 28. Top Marking Explanation

Line 1 Marking: Pin 1 Identifier Circle, 0.5 mm diameter

Product ID 3484A

Line 2 Marking: Firmware revision 01 = Firmware revision 01

Line 3 Marking: TTTTT = Trace Code Manufacturing code characters from the

Markings sectio n of the Assembly Purchase

Order form

Line 4 Marking: YYWW+ = Date Code YY = Last two digits of current year

WW = Current Work Week

Lead Free Designator +

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Silicon Laboratories Inc.

400 West Cesar Chavez

Austin, TX 78701

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