ft232h

Go module for FTDI FT232H USB to GPIO/SPI/I²C/JTAG/UART protocol converter

API features

This software is a work-in-progress (WIP) and not ready for use. The following features have been implemented, but their interfaces maywill change.

• Documented and integration tested
• Multi-platform support (see: build matrix)
  • go1.11,gp1.12,go1.13,go1.14,go1.15,go-master
    • Linux: amd64,386,arm64,arm
    • macOS: amd64
• GPIO - read/write
  • 8 dedicated pins available in any mode
  • 8-bit parallel, and 1-bit serial read/write operations
• SPI - read/write
  • SPI modes 0 and 2 only, i.e. CPHA=1
  • configurable clock rate up to 30 MHz
  • chip/slave-select CS on both ports (pins D3—D7, C0—C7), including:
    • automatic assert-on-write/read with configurable polarity
    • multi-slave support with independent clocks SCLK, SPI modes, CPOL, etc.
  • unlimited effective transfer time/size
    • USB uses 64 KiB packets internally
• I2C - read/write
  • configurable clock rate up to high speed mode (3.4 Mb/s)
  • internal or external SDA pullup option
  • unlimited effective transfer time/size
    • USB uses 64 KiB packets internally
• JTAG - not yet implementented
• UART - not yet implementented
• TBD (WIP)

Installation

If you are not using Go modules for your application (or are unsure), use the built-in go package manager:

go get -u -v github.com/ardnew/ft232h

Otherwise, you are using Go modules, either use the same command above (sans -u), or simply add the import statement to your source code and the module will be installed automatically:

import (
  // ... other imports ...
  "github.com/ardnew/ft232h"
)

No other files or configuration to your build process are necessary.

Linux

Many Linux distributions ship with the FTDI Virtual COM Port (VCP) driver pre-installed (as a kernel module, usually ftdi_sio). However, according to FTDI:

For Linux, Mac OS X (10.4 and later) and Windows CE (4.2 and later) the D2XX driver and VCP driver are mutually exclusive options as only one driver type may be installed at a given time for a given device ID.

There are a lot of ways to resolve the issue, including fancy udev rules to swap out modules when (un)plugging devices, but I don't personally use the VCP driver.

On Ubuntu, you can simply prevent the VCP module from being auto-loaded at bootup by blacklisting the module. For example, create a new file /etc/modprobe.d/blacklist-ftdi.conf with a single directive:

# the official FTDI driver D2XX is incompatible with the VCP driver,
# preventing communication with FT232H breakouts
blacklist ftdi_sio

Be sure to unload the module if it was already loaded:

sudo rmmod ftdi_sio

macOS

Despite FTDI's own quote from the D2XX Programmer's Guide above, I've found that the current versions of macOS (10.13 and later, personal experience) have no problem co-existing with the D2XX driver included with this ft232h Go module. It Just Works and no configuration is necessary.

Documentation

	Markdown	godoc
Primary API reference	github.com/ardnew/ft232h
Supported peripheral devices	github.com/ardnew/ft232h/drv
Native FTDI drivers	github.com/ardnew/ft232h/native

Examples

Demo applications using this module and its device drivers can be found in examples/.

Usage examples for the API can be found in the godoc package documentation.

Notes

Where to get one

Adafruit sells a very nice breakout with a bunch of extras:

• USB-C and Stemma QT/Qwiic I²C connectors (with a little switch to short the chip's two awkward SDA pins!)
• On-board EEPROM (for storing chip configuration)
• 5V (VBUS) and 3.3V (on-board regulator, up to 500mA draw) outputs