BU21021GUL-E2 - Rohm Semiconductor

○Product structure：Silicon monolithic integrated circuit ○This product is not designed protection against radioactive rays

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Datashee

t

4-wire resistive

Touch Screen Controller

BU21021GUL

●General Description

BU21021GUL is a resistive touch screen controller,

which is capable of detecting 2 points touch with a

legacy 4-wire resistive touch screen. BU21021GUL is

capable of detecting X/Y coordinates, touch pressure in

1 point detection mode, and a pair of X/Y coordinates in

2 point detection mode.

It is also capable of recognizing multiple finger gestures

from coordinate data variation and notifying to host with

gesture detection flags respectively.

BU21021GUL employs embedded CPU for noise

filtering, coordinate calculation, gesture detection and

other signal processing required on a chip.

●Feature

■ Legacy 4-wire resistive touch screen is applicable

■ 1 point / 2 points touch detection

■ On chip coordinate generation

■ Multiple gesture detections

■ 3V single power supply

■ Higher coordinate resolution with 12-bit SAR A/D

converter

■ On chip clock generator

■ Selectable HOST I/F(IFSEL pin)

4-wire SPI / 2-wire serial bus

●Key Specification

■ Power supply voltage

■ Temperature range

■ Standby current

■ Sleep current

■ Operating current

■ Coordinate resolution

2.7V to 3.6V

-20℃ to 85℃

5.0uA (Max.)

60uA (Typ.)

4.0mA (Typ.)

12bit

●Package

VCSP50L2 2.70 mm x 2.65 mm x 0.55(max) mm

●Application

■ Equipments with user Interface employing 4-wire

resistive touch screen.

■ Mobile phone, Tablet PC, PDA or other portable

information devices.

■ Digital still camera, Digital video camera, portable TV

or other Audio-visual devices.

■ Note PC, Touch screen monitor, printer or other PC

peripherals.

●Applica tion Circ uit Exa mple

(2-wire serial I/F, Slave address=B8h, non-use EEPROM)

Figure 1. Application circuit example

Datasheet

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BU21021GUL

●Pin Layout

1 2 3 4 5

A T4 PVDD DVDD VDD DVSS

B XP AVDD AVSS DVDD_EXT

C XN YP RSTB T1 T2

D YN SEL_CSB SO T3 IFSEL

E ECL EDA SCL_SCK SDA_SI INT

Top view

Figure 2. Pin Layout

●Pin Descriptions

Pin no. Pin Name I/O Description Equivalent

circuit

D1 YN I/O YN channel input. D

C1 XN I/O XN channel input. D

C2 YP I/O YP channel input. D

B1 XP I/O XP channel input. D

A1 T4 I/O Test input / output. D

A2 PVDD O Regulator output for touch screen voltage supply. D

B3 AVDD O Regulator output for analog circuit. D

A3 DVDD I/O Regulator output for digital circuit D

B4 AVSS - Analog ground. -

A4 VDD - Chip power supply. -

A5 DVSS - Digital ground. -

B5 DVDD_EXT I Digital power supply select. （L=internal、H=external） A

C3 RSTB I Reset (Low active) C

C4 T1 I Test input. A

C5 T2 I Test input. A

D4 T3 I Test input. A

D5 IFSEL I Host interface select. (L=4-wire SPI, H=2-wire serial) A

D3 SO O 2-wire serial High impedance 4-wire SPI Data output E

E5 INT O Interrupt E

D2 SEL_CSB I 2-wire serial Slave address select 4-wire SPI Chip select C

E4 SDA_SI I/O 2-wire serial Data input / output 4-wire SPI Data input B

E3 SCL_SCK I 2-wire serial Clock input 4-wire SPI Clock input B

E2 EDA I/O SDA for EEPROM B

E1 ECL I/O SCL for EEPROM B

(*1) Bypass AVDD and DVDD to GND with 1.0 uF capacitor and PVDD and T4 need terminal opening.

(*2) Digital voltage can be supplied by DVDD when DVDD_EXT=H.

(*3) ECL and EDA need pull-up with 4.7kΩ resister in use case. If not use, connect to GND.

(*4) SCL_SCK and SDA_SI need pull-up with over 4.7kΩ resister and SO need terminal opening when use 2-wire serial I/F.

(*5) Above parameters are only recommended for use. Absolute reliability is not guaranteed.

(*6) When VDD is not supplied, state of RSTB=”H” is prohibition.

Datasheet

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BU21021GUL

●I/O equivalent circuits

Equivalent circuit A Equivalent circuit B

Equivalent circuit C Equivalent circuit D

Equivalent circuit E

Figure 3. I/O equivalent circuits

Datasheet

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BU21021GUL

●Overview

BU21021GUL is a resistive touch screen controller, which is capable of detecting 2 points touch with a legacy 4-wire

resistive touch screen. It is composed of 32-bit CPU, 12-bit SAR A/D converter, clock oscillator, and voltage regulators

power supply, and operates at a single power supply ranging from 2.7 to 3.6V. BU21021GUL is capable of detecting X/Y

coordinates, touch pressure in 1 point detection mode, and a pair of X/Y coordinates in 2 point detection mode.

It is also capable of recognizing multiple finger gestures from coordinate data variation and notifying to host with gesture

detection flags respectively.BU21021GUL employs embedded CPU for noise filtering, coordinate calculation, gesture

detection and other signal processing required on a chip.

BU21021GUL senses panel terminal voltages periodically, filters noise, then calculates coordinates in its operation mode.

Host will be noticed by a interrupt signal (INT) when resister values are updated.

1 point detection

Touch detection and touch pressure detection are processed on chip, and BU21021GUL operates as a legacy

resistive touch controller employing 4-wire resistive touch screen.

BU21021GUL has 2 point touch detection function, which prevents itself from common misdetection of single

‘midpoint’ coordinate output.

2 points detection

2 point detection is held by monitoring electric condition of a touch sensor and calculating coordinates on each axis.

The process is different from legacy 1 point touch detection, therefore BU21021GUL requires setup of panel parameter

in advance.

BU21021GUL automatically detects ether 1 point or 2 points touch input.

Gesture detection

BU21021GUL is able to detect 1 point flick gesture for 4 directions and 2 point ZOOM IN/OUT, PINCH/SPREAD and

rotate gestures respectively. Gesture detection events are reported to host as detection flags and interrupt. Each of

gesture detection sensitivities can be set as register parameters respectively.

(Note) Gesture flags only repot its events. Operation speed and movement have to be calculate on host using

coordinate data.

Auto power on / off function

Auto power off function will power off to sleep condition in order to reduce power consumption when no touch input is

detected. BU21021GUL will automatically change to operation state when touch event is detected in sleep state.

This function is able to be enabled / disabled, and threshold level of sleep state transition is able to be set by registers.

Host interface

BU21021GUL works as slave device of HOST MCU connected 2-wire serial bus or 4-wire SPI.

It is selectable by IFSEL pin condition.

(IFSEL=GND：4-wire SPI、IFSEL=VDD：2-wire serial bus)

EEPROM

Firmware has to be downloaded on BU21021GUL in order to realize these functions. The file size of firmware is 16kB

(16384 bytes). A "HOST interface" and "external EEPROM" can be chosen as the download method.

DVDD external supply setup

In the case there exists 1.8V power supply on application system, the external 1.8V supply can be applicable to DVDD

in order to reduce sleep power consumption to 10uA.

Datasheet

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BU21021GUL

●Block Diagram

Figure 4. Block Diagram

●Description of Blocks

Screen-I/F : 4-wire touch screen interface

ADC : 12-bit SAR A/D converter

OSC : 20MHz oscillator for internal block

Regulator : Internal power supply.

DVDD can be supplied from external

Clock generator : System clock and internal timing generation

CPU : Noise filtering, dual touch detection and touch coordinates generation

Work memory : CPU work memory

Program memory : CPU program memory

EEPROM-I/F : External EEPROM-I/F for CPU program memory downloads

Host-I/F : 4-wire SPI I/F / 2-wire serial bus I/F

Filter : Median average filter (Maximum 16 data)

Datasheet

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BU21021GUL

●Absolute Maximum Ratings

*1 Ambient temperature reduces a permission loss by 9.10mW per case more than 25 degree Celsius, 1degree Celsius. Condition: Assembly on the

Epoxy-Glass (50x58x1.75mm)

●Recommended Operating Conditions

●Electrical Characteristics

At Ta = 25℃, VDD = 3.0V, unless otherwise noted.

*1 The supply of digital power (1.8V) is needed from the terminal DVDD.

Parameter Symbol Rating Unit Conditions

Power-supply voltage VDD -0.3 to 4.5 V

Input voltage VIN VSS-0.3 to VDD+0.3 V

Power dissipation Pd 910*1 mW

Storage temperature range Tstg -50 to 125 ℃

Parameter Symbol

Rating

Unit Conditions

Min Typ Max

Power-supply voltage VDD 2.7 3.0 3.6 V

Digital power-supply voltage DVDD 1.62 1.80 1.98 V DVDD_EXT = H

Operating temperature range Topr -20 25 85 ℃

Parameter Symbol Rating Unit Conditions

Min Typ Max

Low-level input voltage VIL VSS-0.5 - 0.2xVDD V

High-level input voltage VIH 0.8xVDD - VDD+0.5 V

Low-level output voltage VOL - - VSS+0.4 V

High-level output voltage VOH VDD-0.4 - - V

Standby current Ist - - 5 uA RSTB=L

Sleep current1 Icc1 - 60 100 uA DVDD_EXT=L

Sleep current2 Icc2 - 10 20 uA DVDD_EXT=H (*1)

Operating current Idd - 4 8 mA No load

Clock frequency Freq 15 20 24 MHz

Datasheet

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BU21021GUL

●HOST-I/F timing specificatio n (4-wire SPI)

(Note: SCK=SCL_SCK, SI=SDA_SI, CSB=SEL_CSB and SO=SO)

4-wire SPI has the burst write and burst read.

The automatic address increment is done until 0x5F. After address 0x5F is accessed, it is not changed.

WA6 WA5 WA4 WA3 WA2 WA1 WA0 WD7 WD6 WD5 WD4 WD3 WD2 WD1 WD0 WD7 WD6 WD1 WD0

RA6RA5RA4RA3RA2RA1RA0

RD7 RD6 RD5 RD4 RD3 RD2 RD1 RD0 RD7 RD6 RD1 RD0 RD7

CSB

SCK

SI

write

SI

read

SO

read

Register address Write (WA) Write (WA + 1) Write (WA + n)

Register address

Read (RA) Read (RA + 1) Read (RA + n)

HiZ HiZ

t1

t2t3t4t5t8t9

t6 t7

W/R

Figure 5. Timing specification (4-wire SPI)

Table 1. Timing Requirements: 4-wire SPI at VDD = 3.0V, Ta = 25℃

Parameter Symbol Rating Unit Conditions

Min Typ Max

CSB setup time t1 30 - - ns

‘H’ width of SCK t2 30 - - ns

‘L’ width of SCK t3 30 - - ns

SI setup time t4 20 - - ns

SI holding time t5 20 - - ns

CSB holding time t6 20 - - ns

‘H’ width of CSB t7 50 - - ns

SO output delay time t8 - - 15 ns

SCK frequency t9 - - 15 MHz

Datasheet

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BU21021GUL

●HOST-I/F timing specificatio n (2-wire serial)

(Note: SCL=SCL_SCK, SDA=SDA_SI)

2-wire serial has the burst write and burst read.

The automatic address increment is done until 0x5F. After address 0x5F is accessed, it is not changed.

This 2-wire serial I/F is not corresponded to re-start command. Send start condition after send stop condition.

The slave address of 2-wire serial is B8h / BAh which is decided by the state of the terminal SEL_CSB.

SEL_CSB = “L” : Slave Address = B8h ( 7bit = 5Ch + W/R bit )

SEL_CSB = “H” : Slave Address = BAh ( 7bit = 5Dh + W/R bit )

Figure 6. Timing specification (2-wire serial)

Table 2. Timing Requirements: 2-wire serial at VDD = 3.0V, Ta = 25℃

Parameter Symbol Rating Unit Condition

Min Typ Max

SCL clock frequency fSCL 0 - 400 kHz

START hold time tHD:STA 0.6 - - us

"L" width of SCL tLOW 1.3 - - us

"H" width of SCL tHIGH 0.6 - - us

Data hold time tHD:DAT 0.1 - - us

Data setup time tSU:DAT 0.1 - - us

STOP setup time tSU:STO 0.6 - - us

・Write Protocol

S SLAVE

ADDRESS W A REGISTER

ADDRESS AWRITE

DATA AP

7bit = 5Ch or 5Dh 8bit 8bit

・Read Protocol

S SLAVE

ADDRESS W A REGISTER

ADDRESS APS SLAVE

ADDRESS RA READ

DATA NP

7bit = 5Ch or 5Dh 8bit 7bit = 5Ch or 5Dh 8bit

from Master to Slave S : START condition

from Slave to Master P : STOP condition

R : data direction READ (SDA HIGH)

W : data direction WRITE (SDA LOW)

A : acknowledge (SDA LOW)

N : not acknowledge (SDA HIGH)

Figure 7. Read/Write Protocol

Datasheet

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BU21021GUL

●Typical Application circuit

BU21021GUL has two selectable host interfaces (4-wire SPI and 2-wire serial).

The figure below shows the example of circuit when each interface is used.

(Show by the terminal display though BU21021GUL is CSP package.)

Option(*1) For reject and reduce the noise from touch screen / LCD module or wiring.

Option(*2) It is not necessary to mount EEPROM when firmware download setting is host.

Connect to ECL/EDA to VSS.

Please connect EEPROM when firmware download setting is EEPROM.

Option(*3) In using with Slave address = BAh case, connect SEL_CSB to VDD.

Figure 8. Application circuit 1 (4-wire SPI)

Figure 9. Application circuit 2 (2-wire serial bus)

Datasheet

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BU21021GUL

●Ordering Information

●Physical Dimension Tape and Reel Information

●Marking Diagram(TOP VIEW)

BU 21021GUL-E2

Package Tape and Reel information

GUL: VCSP50L2 E2: Embossed carrier tape

Part Number

∗

Order quantity needs to be multiple of the minimum quantity.

Embossed carrier tapeTape

Quantity

Direction

of feed The direction is the 1pin of product is at the upper left when you hold

reel on the left hand and you pull out the tape on the right hand

3000pcs

E2

()

Direction of feed

Reel 1pin

Datasheet

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BU21021GUL

Revision History

Date Revision Changes

2012/06/19 001 New Release

2016/11/30 002

P1 Correct temperature range

(old) -25℃ to 85℃

(new) -20℃ to 85℃

P1, P9 Change application circuit

Add capacitor between VDD and ground

Change the symbol of ESD protection diode

Notice-PGA-E Rev.003

Notice

Precaution on using ROHM Products

1. Our Products are designed and manufactured for application in ordinary electronic equipments (such as AV equipment,

OA equipment, telecommunication equipment, home electronic appliances, amusement equipment, etc.). If you

intend to use our Products in devices requiring extremely high reliability (such as medical equipment (Note 1), transport

equipment, traffic equipment, aircraft/spacecraft, nuclear power controllers, fuel controllers, car equipment including car

accessories, safety devices, etc.) and whose malfunction or failure may cause loss of human life, bodily injury or

serious damage to property (“Specific Applications”), please consult with the ROHM sales representative in advance.

Unless otherwise agreed in writing by ROHM in advance, ROHM shall not be in any way responsible or liable for any

damages, expenses or losses incurred by you or third parties arising from the use of any ROHM’s Products for Specific

Applications.

(Note1) Medical Equipment Classification of the Specific Applications

JAPAN

USA

EU

CHINA

CLASSⅢ

CLASSⅡb

CLASSⅢ

CLASSⅣ

CLASSⅢ

2. ROHM designs and manufactures its Products subject to strict quality control system. However, semiconductor

products can fail or malfunction at a certain rate. Please be sure to implement, at your own responsibilities, adequate

safety measures including but not limited to fail-safe design against the physical injury, damage to any property, which

a failure or malfunction of our Products may cause. The following are examples of safety measures:

[a] Installation of protection circuits or other protective devices to improve system safety

[b] Installation of redundant circuits to reduce the impact of single or multiple circuit failure

3. Our Products are designed and manufactured for use under standard conditions and not under any special or

extraordinary environments or conditions, as exemplified below. Accordingly, ROHM shall not be in any way

responsible or liable for any damages, expenses or losses arising from the use of any ROHM’s Products under any

special or extraordinary environments or conditions. If you intend to use our Products under any special or

extraordinary environments or conditions (as exemplified below), your independent verification and confirmation of

product performance, reliability, etc, prior to use, must be necessary:

[a] Use of our Products in any types of liquid, including water, oils, chemicals, and organic solvents

[b] Use of our Products outdoors or in places where the Products are exposed to direct sunlight or dust

[c] Use of our Products in places where the Products are exposed to sea wind or corrosive gases, including Cl2,

H2S, NH3, SO2, and NO2

[d] Use of our Products in places where the Products are exposed to static electricity or electromagnetic waves

[e] Use of our Products in proximity to heat-producing components, plastic cords, or other flammable items

[f] Sealing or coating our Products with resin or other coating materials

[g] Use of our Products without cleaning residue of flux (even if you use no-clean type fluxes, cleaning residue of

flux is recommended); or Washing our Products by using water or water-soluble cleaning agents for cleaning

residue after soldering

[h] Use of the Products in places subject to dew condensation

4. The Products are not subject to radiation-proof design.

5. Please verify and confirm characteristics of the final or mounted products in using the Products.

6. In particular, if a transient load (a large amount of load applied in a short period of time, such as pulse. is applied,

confirmation of performance characteristics after on-board mounting is strongly recommended. Avoid applying power

exceeding normal rated power; exceeding the power rating under steady-state loading condition may negatively affect

product performance and reliability.

7. De-rate Power Dissipation depending on ambient temperature. When used in sealed area, confirm that it is the use in

the range that does not exceed the maximum junction temperature.

8. Confirm that operation temperature is within the specified range described in the product specification.

9. ROHM shall not be in any way responsible or liable for failure induced under deviant condition from what is defined in

this document.

Precaution for Mounting / Circuit board design

1. When a highly active halogenous (chlorine, bromine, etc.) flux is used, the residue of flux may negatively affect product

performance and reliability.

2. In principle, the reflow soldering method must be used on a surface-mount products, the flow soldering method must

be used on a through hole mount products. If the flow soldering method is preferred on a surface-mount products,

please consult with the ROHM representative in advance.

For details, please refer to ROHM Mounting specification

Notice-PGA-E Rev.003

Precautions Regarding Application Examples and External Circuits

1. If change is made to the constant of an external circuit, please allow a sufficient margin considering variations of the

characteristics of the Products and external components, including transient characteristics, as well as static

characteristics.

2. You agree that application notes, reference designs, and associated data and information contained in this document

are presented only as guidance for Products use. Therefore, in case you use such information, you are solely

responsible for it and you must exercise your own independent verification and judgment in the use of such information

contained in this document. ROHM shall not be in any way responsible or liable for any damages, expenses or losses

incurred by you or third parties arising from the use of such information.

Precaution for Electrostatic

This Product is electrostatic sensitive product, which may be damaged due to electrostatic discharge. Please take proper

caution in your manufacturing process and storage so that voltage exceeding the Products maximum rating will not be

applied to Products. Please take special care under dry condition (e.g. Grounding of human body / equipment / solder iron,

isolation from charged objects, setting of Ionizer, friction prevention and temperature / humidity control).

Precaution for Storage / Transportation

1. Product performance and soldered connections may deteriorate if the Products are stored in the places where:

[a] the Products are exposed to sea winds or corrosive gases, including Cl2, H2S, NH3, SO2, and NO2

[b] the temperature or humidity exceeds those recommended by ROHM

[c] the Products are exposed to direct sunshine or condensation

[d] the Products are exposed to high Electrostatic

2. Even under ROHM recommended storage condition, solderability of products out of recommended storage time period

may be degraded. It is strongly recommended to confirm solderability before using Products of which storage time is

exceeding the recommended storage time period.

3. Store / transport cartons in the correct direction, which is indicated on a carton with a symbol. Otherwise bent leads

may occur due to excessive stress applied when dropping of a carton.

4. Use Products within the specified time after opening a humidity barrier bag. Baking is required before using Products of

which storage time is exceeding the recommended storage time period.

Precaution for Product Label

A two-dimensional barcode printed on ROHM Products label is for ROHM’s internal use only.

Precaution for Disposition

When disposing Products please dispose them properly using an authorized industry waste company.

Precaution for Foreign Exchange and Foreign Trade act

Since concerned goods might be fallen under listed items of export control prescribed by Foreign exchange and Foreign

trade act, please consult with ROHM in case of export.

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1. All information and data including but not limited to application example contained in this document is for reference

only. ROHM does not warrant that foregoing information or data will not infringe any intellectual property rights or any

other rights of any third party regarding such information or data.

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Products with other articles such as components, circuits, systems or external equipment (including software).

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third parties with respect to the Products or the information contained in this document. Provided, however, that ROHM

will not assert its intellectual property rights or other rights against you or your customers to the extent necessary to

manufacture or sell products containing the Products, subject to the terms and conditions herein.

Other Precaution

1. This document may not be reprinted or reproduced, in whole or in part, without prior written consent of ROHM.

2. The Products may not be disassembled, converted, modified, reproduced or otherwise changed without prior written

consent of ROHM.

3. In no event shall you use in any way whatsoever the Products and the related technical information contained in the

Products or this document for any military purposes, including but not limited to, the development of mass-destruction

weapons.

4. The proper names of companies or products described in this document are trademarks or registered trademarks of

ROHM, its affiliated companies or third parties.

DatasheetDatasheet

Notice – WE Rev.001

General Precaution

1. Before you use our Pro ducts, you are requested to care fully read this document and fully understand its contents.

ROHM shall n ot be in an y way responsible or liabl e for fa ilure, malfunction or acci dent arising from the use of a ny

ROHM’s Products against warning, caution or note contained in this document.

2. All information contained in this docume nt is current as of the issuing date and subj ect to change without any prior

notice. Before purchasing or using ROHM’s Products, please confirm the la test information with a ROHM sale s

representative.

3. The information contained in this doc ument is provi ded on an “as is” basis and ROHM does not warrant that all

information contained in this document is accurate an d/or error-free. ROHM shall not be in an y way responsible or

liable for an y damages, expenses or losses incurred by you or third parties resulting from inaccur acy or errors of or

concerning such information.