Bit-Banging The SPI Bus and PiFace

Among the Diagnostic & Test programs released last week there was one called PiMCP23S17_manager.py that was intended to facilitate the examination and control of an MCP23S17 device's GPIO ports to a greater extent than is possible with the PiFace "emulator".  Today, PiMCP23S17_manager.py has been upgraded to incorporate changes that permit examination and control of all operating modes of the MCP23S17 device.  If your interest in the MCP23S17 (or PiFace) extends beyond the simplistic, you will possibly find this program interesting or useful.  It can be downloaded from here.
I hope this program will help to extend your appreciation and understanding of the MCP23S17, a remarkably flexible and capable device for expanding the Raspberry Pi's potential.

InterSPi (above) is a project of the "conjoined series", intended for conjoined use with InterPi and/or MegaWire and/or InterHub but it is also suitable for separate use.  Details can be found here.