pyft4222

PyFT4222

A libft4222 library python wrapper.

Description

Building

Run the create_dev_env.sh command to create a virtual environment suitable for development:

./create_dev_env.sh

Installation

The pyft4222 package can be installed using pip:

pip install pyft4222

Use virtual environment preferably.

udev rule

The FT4222 device is not accessible by all users by default. You can create a rule in /etc/udev/rules.d/99-ftdi.rules to make the device available to all users.

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

Documentation

Use mypy or other language server that supports Python types. Library functions are easier to use with type hints.

WIP

Examples

Open an SPI master stream:

from koda import Err, Ok
import pyft4222 as ft
from pyft4222.stream import InterfaceType
from pyft4222.wrapper.spi import ClkPhase, ClkPolarity
from pyft4222.wrapper.spi.master import ClkDiv, SsoMap

# Print out list of connected devices
for dev in ft.get_device_info_list():
    print(dev)

# Open device using 'device index'
dev = ft.open_by_idx(0)

# Check if it was opened successfully
# If using Python < 3.10, use "isinstance(dev, Ok)"
match dev:
    case Ok(handle):

        # Check if the FT4222 mode is as expected
        if handle.tag == InterfaceType.DATA_STREAM:

            # Use context manager to close the handle automatically at the end of scope
            with handle:

                # Initialize FT4222 in SPI master mode using a single-bit
                # full-duplex transfer
                with handle.init_single_spi_master(
                    ClkDiv.CLK_DIV_2,
                    ClkPolarity.CLK_IDLE_LOW,
                    ClkPhase.CLK_TRAILING,
                    SsoMap.SS_0,
                ) as spi_master:

                    # Write and read back data simultaneously
                    read_data = spi_master.single_read_write(
                        bytes([0x01, 0x02, 0x03, 0x04])
                    )

                    print("Data read: ")
                    print(read_data)

        else:
            print("FT4222 is in invalid mode!")

    case Err(err):
        print("Couldn't open the handle")
        print(err)

Open an I2C slave stream:

import pyft4222 as ft
from pyft4222.stream import InterfaceType

from koda import Err, Ok

# Print out list of connected devices
for dev in ft.get_device_info_list():
    print(dev)

# Open device using 'device index'
dev = ft.open_by_idx(0)

# Check if it was opened successfully
# If using Python < 3.10, use "isinstance(dev, Ok)"
match dev:
    case Ok(handle):
        # Check if the FT4222 mode is as expected
        if handle.tag == InterfaceType.DATA_STREAM:
            # The handle is closed automatically at the end of scope
            with handle:
                # Initialize the FT4222 in I2C slave mode
                # The handle is uninitialized automatically at the end of scope
                with handle.init_i2c_slave() as iic_slave:
                    # Set an I2C device address
                    iic_slave.set_address(0x0340)

                    # Write data into the device buffer
                    iic_slave.write(bytes([0xFF, 0x01, 0x02, 0x03]))

        else:
            print("FT4222 is in invalid mode!")

    case Err(err):
        print("Couldn't open the handle")
        print(err)

Open GPIO stream:

from koda import Err, Ok
import pyft4222 as ft
from pyft4222.stream import InterfaceType
from pyft4222.wrapper.gpio import Direction, PortId

# Print out list of connected devices
for dev in ft.get_device_info_list():
    print(dev)

# Open device using 'device index'
result = ft.open_by_idx(0)

# Check if it was opened successfully
# If using Python < 3.10, use "isinstance(dev, Ok)"
match result:
    case Ok(handle):
        # Check if the FT4222 mode is as expected
        if handle.tag == InterfaceType.GPIO:
            # The handle is automatically closed at the end of the scope
            with handle:
                # The handle is automatically uninitialized at the end of the scope
                with handle.init_gpio(
                    (
                        Direction.OUTPUT,
                        Direction.INPUT,
                        Direction.OUTPUT,
                        Direction.OUTPUT,
                    )
                ) as gpio:
                    # Disable suspend out, else we cannot control GPIO2
                    gpio.set_suspend_out(False)
                    # Disable wakeup interrupt, else we cannot control GPIO3
                    gpio.set_wakeup_interrupt(False)

                    # Set GPIO port 0 into a logical 1 state
                    gpio.write(PortId.PORT_0, True)

                    # Read GPIO port 1 input state
                    port1_state = gpio.read(PortId.PORT_1)
                    print(port1_state)

        else:
            print("FT4222 is in invalid mode!")

    case Err(err):
        print("Couldn't open the handle")
        print(err)