FTDI serial chip emulation for LUFA

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.