FTDI serial chip emulation for LUFA

Written by Jim Paris jim@jtan.com

Description

This project is an example of FTDI usb-to-serial chip emulation for LUFA. It is fully interrupt-driven. It acts as a FT232RL with id 0403:6001. On Linux, the corresponding host driver is ftdi_sio.

Note that it's probably against the EULA of the proprietary FTDI Windows driver to use it with non-FTDI hardware. And using someone else's VID will prevent you from passing USB-IF compliance tests.

Building

git submodule init
git submodule update
make

Configuration

Basic configuration of the FTDI emulation is in ftdi.h. Read and write buffers are maintained in a FIFO queue of length FTDI_TX_QUEUE_LEN and FTDI_RX_QUEUE_LEN. The latter must be greater than the endpoint size. For a smaller memory footprint, FTDI_TXRX_EPSIZE can be reduced (try 16).

Initialization

Call void ftdi_init(int flags) after the corresponding LUFA USB_Init(). Valid flags are a bitwise OR of the following:

FTDI_NO_STDIO     Don't reconfigure libc's stdio
FTDI_STDIO        Point stdio routines to ftdi_putchar / ftdi_getchar

FTDI_NONBLOCKING  Neither ftdi_putchar nor ftdi_getchar will block.
FTDI_BLOCKING_IN  ftdi_getchar will block if no data is available
FTDI_BLOCKING_OUT ftdi_putchar will block is no room in TX buffer
FTDI_BLOCKING     Both ftdi_getchar and ftdi_putchar will block

When input is nonblocking, ftdi_getchar will return -1 if no data is available. When output is nonblocking, ftdi_putchar will drop data if no TX buffer space is available. Regardless of blocking status, if the RX buffer is full, data received from the PC will be dropped.

License

BSD 2-clause, see LICENSE