Copyright © Future Technology Devices International Limited 10
FT4222H USB2.0 TO QUADSPI/I2C BRIDGE IC
Version 1.4
Document No.: FT_001011 Clearance No.: FTDI#405
4 Function Description
The FT4222H is a Hi-Speed USB2.0-to-Quad SPI/ I2C device controller in a compact 32-pin VQFN
package. The FT4222H requires an external Crystal (12 MHz) for the internal PLL to operate. It supports
multi-voltage IO, 3.3V, 2.5V or 1.8V. It also provides 128 bytes one-time-programmable (OTP) memory
space for storing vendor specific information.
The FT4222H contains SPI/ I2C configurable interfaces. The SPI interface can be configured in master
mode with single, dual, or quad bits data width transfer or in slave mode with single bit data width
transfer. The I2C interface can be configured in master or slave mode.
4.1 Key Features
Functional Integration. The FT4222H is a USB 2.0 Hi-Speed (480Mbits/s) to flexible and configurable
SPI or I2C interfaces IC. The FT4222H includes an integrated +1.8V and +3.3V Low Drop-Out (LDO)
regulator and 12MHz to 480MHz PLL. It also includes Power-On-Reset (POR), VBUS detection with 5V-
tolerance and 128 bytes one-time-programmable (OTP) memory which simplify external circuit design
and reduce external component count.
USB2.0 Hi-Speed Device Controller. The FT4222H integrates a USB protocol engine which controls the
physical Universal Transceiver Macrocell Interface (UTMI) and handles all aspects of the USB 2.0 Hi-
Speed interface. It contains one control endpoint, and 4-pairs of IN and OUT endpoints. These endpoints
can implement up to 4 independent interfaces/applications mapped to combined I2C, GPIO, SPI interfaces.
Highly Integrated USB2.0 to Configurable SPI Bridge. The FT4222H provides the bridge function
between a USB2.0 device, upstream port and an SPI Master/Slave.
A support library, LibFT4222, based on FTDI’s D2XX driver, enables easy configuration of the SPI as a
master or slave. Operating clock frequency on the SPI bus, clock phase and polarity, transfer data bit
width mode, and the number of slave selection controls are also configurable.
The maximum SPI interface operating clock can be set up to 40MHz in master mode and 20MHz in slave
mode. With quad mode (4-bits) data bus width, the max data transfer throughput can be up to 53.8Mbps.
USB to Configurable I2C Controller. The FT4222H also provides the bridge function between a USB2.0
device upstream port and an I2C Master/Slave interface.
A support library, LibFT4222, based on FTDI’s D2XX driver, enables easy configuration of the I2C as
either a master or slave, including target operating speed and bus protocol on the I2C bus.
The device can run at common I2C bus speeds, standard mode (SM), fast mode (FM), Fast mode plus
(FM+), and High Speed mode (HS). A higher bit rate on the I2C bus is also configurable up to 6.66Mbit/s.
Clock stretching is supported to conform to v2.1 and v3.0 of the I2C specification.
Configurable GPIOs. There are 4 GPIO pins in the FT4222H that can be configured for different
purposes, such as a suspend indicator output, remote wake up input, an interrupt input or general
purpose Input/Output. These GPIOs can be easily initialized and fully controlled at the USB host side by
the application programming interface (API) defined in LibFT4222.
Signal drive strength and slew rate of these GPIOs can be configured via the FT_Prog utility for different
design needs.
Embedded OTP memory. The internal OTP memory in the FT4222H is used to store USB Vendor ID
(VID), Product ID (PID), device serial number, product description string and various other USB
configuration descriptors. With this embedded OTP memory, the device can store vendor specific
information and save the cost on BOM. The descriptors can be programmed using the FTDI utility
software called FT_PROG, which can be downloaded from the FTDI Utilities page on the FTDI website
(http://www.ftdichip.com/Support/Utilities.htm#FT_Prog).
Power management. USB 2.0 suspend/resume and remote wakeup are fully supported. The PHY will be
put to a power saving mode and the clock to most of the digital circuits will be stopped when the device
is suspended.
Source Power and Power Consumption. The FT4222H is capable of operating at a voltage supply of
+3.3V or +5.0V with a nominal operational mode current of 68mA and a nominal USB suspend mode
current of 375µA. This allows greater margin for peripheral designs to meet the USB suspend mode
current limit of 2.5mA. An integrated level converter within the FT4222H allows the device to interface
with logic running at +1.8V, +2.5V or +3.3V. (Note: External pull-ups are recommended for IO <3V3).