Towards an FT232 Driver for the USB Host Shield- Part 0

FTDI232RL IC on a breakout board

FTDI232RL IC on a breakout board

Based on some discussion on the Arduino Forum, Richard has added this blog entry as work in progress on developing a library to support FTDI Serial port devices on the USB Host Shield. While cautious to publish at this early testing stage, the content here should help parallel developers.

My thoughts last year were that an FT232 driver for the Host Shield was not really useful. It seemed rather reverse to add a USB host plus a USB device to achieve something that can be done with a piece of wire. However USB is coming to be the baseline interface and is now the only interface offered on many serial devices.

USB Shield Hardware
Since my last blog update, Sparkfun have released their own version of the USB Host Shield. Great to have another source of the shield, with good stock at many International Sparkfun distributors. However they did add a couple of problems too:
Sparkfun swapped the RESET and the GPX pins from the original from Oleg. This means the shield will not work with the libraries from Oleg without a modification.
The current Max3421e_constants.h from Oleg has:

/* Arduino pin definitions for USB Host Shield signals. They can be changed here or while calling constructor */
#define MAX_SS 10
#define MAX_INT 9
//#define MAX_GPX 8
#define MAX_RESET 7

These work for the shield from Oleg, and existing published code and libraries without change.

However for the Sparkfun Shield they must be changed in Max3421e_constants.h, or optionally changed when the constructor is called to:

#define MAX_SS 10
#define MAX_INT 9
//#define MAX_GPX 7
#define MAX_RESET 8

Continue reading Towards an FT232 Driver for the USB Host Shield- Part 0