piątek, 11 lipca 2014

The second RaspFPGA mezzanine board for Raspberry Pi

This is the second version of the extension card for Raspberry Pi. As the previous one, this circuit connects all GPIO pins of Raspberry Pi to the FPGA chip. I've made a few modifications. Version 2 uses Spartan6 instead of Spartan3, it has 64MB of SDRAM and a small flash memory to store FPPGA configuration. It still leaves all remaining inputs/outputs pins of FPGA for the final user. Now the pin available are less than before because SDRAM occupies many of them. To do not loose this feature one can choose between having SDRAM or having all GPIO available. The choice is done by soldering jumpers in the appropriate places.

Pic. 1 - RaspFPGA v2 board.
The circuit is mechanically and electrically compatible with LCD TFTDisp 4 RaspPAR design published on my blog in March. It contains 25MHz clock source for FPGA, USB to RS232 converter and real time module.