SPI Driver by Excamera Labs

SPIDriver is an easy-to-use tool for controlling SPI devices and a great tool to help with quick driver development and debugging. It works with Windows, Mac, and Linux, and has a built-in color screen that shows a live logic-analyzer display of all SPI traffic. It uses a standard FTDI USB serial chip to talk to the PC, so no special drivers need to be installed. The board includes 3.3 and 5 V supplies with voltage and current monitoring. It's kinda like a Bus Pirate with a display and great Python support.

If you use SPI devices - LCD panels, flash memory, sensors, LEDs - you’ll know that the most frequently asked question is “what’s it doing now?” SPIDriver shows you what’s happening on the SPI bus in real time, so no more guessing about the bus state. It’s designed to make talking to SPI hardware a smooth, intuitive process. That’s good whether you’re a hardware debug wizard or are introducing a class to SPI for the first time.