ft4222

python-ft4222

The FT4222H is a High/Full Speed USB2.0-to-Quad SPI/I2C device controller. This project provides (incomplete) python binding to LibFT4222 (user guide). It provides a similar api than LibFT4222 does.

The complete documentation can be found here

Example

I2C Master

import ft4222
import ft4222.I2CMaster


# list devices
nbDev = ft4222.createDeviceInfoList()
for i in range(nbDev):
    print(ft4222.getDeviceInfoDetail(i, False))

# open device with default description 'FT4222 A'
dev = ft4222.openByDescription('FT4222 A')

# init i2c master, clock speed 100kHz
dev.i2cMaster_Init(100)

# do a i2c transfers where full control is required
slave = 1 # address
# read one byte, don't stop
data = dev.i2cMaster_ReadEx(slave, ft4222.I2CMaster.Flag.REPEATED_START, 1)[0]
# read another 5 bytes
data += dev.i2cMaster_ReadEx(slave, ft4222.I2CMaster.Flag.NONE, 5)
# another byte, than stop
data += dev.i2cMaster_ReadEx(slave, ft4222.I2CMaster.Flag.STOP, 1)

GPIO

import time
import ft4222
from ft4222.GPIO import Dir, Port, Output

# open device with default description 'FT4222 A'
dev = ft4222.openByDescription('FT4222 A')

# use GPIO2 as gpio (not suspend out)
dev.setSuspendOut(False)
# use GPIO3 as gpio (not wakeup)
dev.setWakeUpInterrupt(False)

# init GPIO2 as output
dev.gpio_Init(gpio2 = Dir.OUTPUT)

# generate a square wave signal with GPIO2
while True:
    dev.gpio_Write(Port.P2, output)
    output = not output
    time.sleep(0.1)

SPI Master and GPIO

The gpio used in this example indicate the duration of the whole spi transfer and is not used as chip/slave select.

import ft4222
from ft4222.SPI import Cpha, Cpol
from ft4222.SPIMaster import Mode, Clock, SlaveSelect
from ft4222.GPIO import Port, Dir
from time import sleep

# open 'device' with default description 'FT4222 A'
devA = ft4222.openByDescription('FT4222 A')
# and the second 'device' on the same chip
devB = ft4222.openByDescription('FT4222 B')

# init spi master
devA.spiMaster_Init(Mode.SINGLE, Clock.DIV_8, Cpol.IDLE_LOW, Cpha.CLK_LEADING, SlaveSelect.SS0)
# also use gpio
devB.gpio_Init(gpio0 = Dir.OUTPUT)

# generate data to send
data = bytes([x for x in range(256)]*4)

# set port0 1 (-> note this is *not* the spi chip select, the chip select (SS0) is generated by the spi core)
devB.gpio_Write(Port.P0, 1)

for _ in range(3):
    # write data in a single write
    devA.spiMaster_SingleWrite(data, True)
    # wait a short while
    sleep(0.5)

# set port0 0
devB.gpio_Write(Port.P0, 1)

Accessrights

Under Linux, the usb device is normally not accessibly by a normal user, therefor a udev rule is required. Create or extend /etc/udev/rules.d/99-ftdi.rules to contain the following text:

# FTDI's ft4222 USB-I2C Adapter
SUBSYSTEM=="usb", ATTRS{idVendor}=="0403", ATTRS{idProduct}=="601c", GROUP="plugdev", MODE="0666"

Requirements

Windows

MSVCR100.dll/MSVCP100.dll from Microsoft Visual C++ 2010 Redistributable Package need to be installed. Today, on most systems, these DLLs (or the package) should already be installed.