Darren pointed out two IC demonstration boards from Microchip.
The PICKit Serial I2C demo board has five unique devices with I2C interfaces. It includes a 2Kbit serial EEPROM, high accuracy temperature sensor, 12-bit ADC, 10-bit DAC, and an 8-bit IO expander – all great chips for a new hardware hacker. Debugging is possible through test points on the I2C bus and most of the devices.
The PICKit Serial SPI demo board contains seven unique devices with SPI interfaces including a 2Kbit serial EEPROM, high accuracy temperature sensor, 12-bit ADC, 12-bit DAC, digital potentiometer, a single ended low gain PGA, and an 8-bit IO expander. As with the I2C demo board, it has test points on the SPI bus and most of the attached devices. The only drawback is that all seven devices share the same CS pin, Chip Select just became select all chips! A jumper near each chip selects the slave that’s connected to the bus.
Both demo boards are designed to be used with a PICKit2, however the Bus Pirate can easily interface either of the demo boards. At $25 and $35 these boards are the same price as the Bus Pirate itself – could be a good rebuild candidate if you have the SMD soldering skills.
You can get a Bus Pirate for $30, including worldwide shipping.
Those demo boards aren’t for the PICkit2, they’re for the PICkit Serial Analyzer, which looks an awful lot like a Bus Pirate on steroids:
http://www.microchip.com/stellent/idcplg?IdcService=SS_GET_PAGE&nodeId=1406&dDocName=en028600
If you’re looking for more feature ideas for the next Bus Pirate firmware update, you might want to browse through that user manual.
I especially like the PIC-based demo board they provide for it, which emulates several I2C devices at once; I’d been thinking about doing something similar as an exercise, and now I can point to a practical application for such a project.