The USB Bus Pirate is a great project that can be used for testing new chips without writing any code. It is a universal serial interface device that is connected to the PC using the USB port. The Bus Pirate currently supports serial protocols such as 1-Wire, I2C, SPI, JTAG, asynchronous serial and also has many other various features including PWM, frequency and voltage measurement, bus sniffers, pull-up resistors, and switchable 3.3volt and 5volt power supplies. The device receives commands from the user via a serial terminal.
The brain of the Bus Pirate is the PIC24FJ64GA002 microcontroller from Microchip, which is powered by a 3.3volt regulator. The programming pins are connected to a five pin header located on the lower edge of the PCB. The Bus Pirate is powered using the 5v supply at the USB port which is filtrated using a ferrite bead and a capacitor. The USB to serial connection is done using the FT232BL USB UART chip from FTDI.
The device possesses both 3.3v and 5v switchable supplies that are deactivated by default until a command is given. The circuit can be reset from software if needed. Also, the Bus Pirate has a CD4066BC quad bilateral switch that gives control over multi-voltage pull-up resistors, four voltage dividers connected to A/D converters which enable the pic to measure up to 6v DC, and three LEDs for power, mode, and voltage regulator status located on the upper side of the PCB.
The latest firmware of the Bus Pirate contains a modified bootloader from Microchip, so the firmware can be upgraded using the USB or the serial connection. A detailed procedure of upgrading is available in the link, as well as parts list, pictures and schematics. The Bus Pirate is available for purchase from Hackaday with worldwide shipping at $30.
USB Bus Pirate: [Link]