Philip Balister wrote:
OK, this worked out to be pretty easy. It turns out all the wires on the Spartan board are not needed, just remove the jumper on JP9 so the VCCB0 line is floating.
I was wondering if that would be the case. Yay!
I've tested this on the sample code (that uses the picoblaze) from the Xilinx web site. I had to change the levels on the pins and move the clock pin. The LED's are dimmer since they are powered from bank 0. These pins also run to the prototyping board, so I'll need to avoid using them when I connect the expansion signals to the FPGA.
One of my projects uses the expansion pins that also drive the LEDs as part of a processor interface bus to the FPGA from an ARM. Having the LEDs on the bus doesn't seem to bother it any - they light up dimly and flicker as different data passes over the bus. Not ideal, but I wouldn't have had enough I/O otherwise. I would imagine that at 1.8V they would present an even smaller load than they do at the 3.3V levels I'm using.
Eric
