didactek/ftdi-synchronous-serial SIMPLE-USB-FORKPOINT

A lean stack written primarily in Swift for using the FTDI FT232H USB-to-serial adapter in I2C, SPI, and GPIO applications.

⭐️ 4

🕓 2 years ago

.package(url: "https://github.com/didactek/ftdi-synchronous-serial.git", from: "SIMPLE-USB-FORKPOINT")

FTDI Synchronous Serial

A lean stack written primarily in Swift for using the FTDI FT232H USB-to-serial adapter in I2C, SPI, and GPIO applications, built on the portable C-library libusb.

Overview

This library provides

support for a USB-connected FTDI device in MPSSE mode
implementations of I2C and SPI protocols
uses deft-simple-usb for usermode access to the FTDI device

Synchronous serial communication is data that is timed according to a separate clock signal. While the FTDI also supports asynchronous [UART] communications (such as RS-232), the operating system likely provides support for this mode through one of the /dev/cuserial special devices.

Requirements

Swift Package Manager
Swift 5.3+
macOS or Linux
for FTDI serial devices: an FT232H connected via USB

Mac requirements

macOS 10.15 (Catalina) or higher

SPM Dependencies

swift-log

Linux dependencies

libusb

Goals

make installation and use as easy as possible
minimize additions to the user's environment
use usermode drivers
avoid components that require root access to install or configure
use Swift as much as possible
aspire to code that is readable and idiomatic

Usage

Logging

Loggers are instantiated using the deft-log library using the label prefix com.didactek.ftdi-synchronous-serial.

Installation Notes

Linux device permissions

On Linux, users will not have access to a hot-plugged FTDI device by default. The cleanest way to systematically grant permissions to the device is to set up a udev rule that adjusts permissions whenever the device is connected.

The paths and group in the template below assume:

Configuration files are under /etc/udev/rules.d
The group 'plugdev' exists and includes the user wanting to use the device

Under /etc/udev/rules.d/, create a file (suggested name: "70-gpio-ftdi-ft232h.rules") with the contents:

# FTDI FT232H USB -> GPIO + serial adapter
# 2020-09-07 support working with the FT232H using Swift ftdi-synchronous-serial library
ACTION=="add", SUBSYSTEM=="usb", ATTRS{idVendor}=="0403", ATTRS{idProduct}=="6014", MODE="660", GROUP="plugdev"

eLinux.org has a useful wiki entry on accessing devices without sudo.

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