Hi all
I am trying to program the Vertex 4 FPGA (XC4VFX100) in the slave serial mode using a PIC.
I am facing a problem while doing the programming.
when I am sending the first configuration bit on the din pin of the FPGA , the prog_b & the init_b pins which were otherwise high are going low.
can anybody suggest me about the problem and any solution for this.
thanks & regards archana
The prog_b pin should not be driven by the FPGA. If the PIC is the only other thing connected to the net, I would suggest checking your PIC program. If the PIC is not actively driving prog_b high, you should have a pullup resistor on the net.
The init_b pin will go low when prog_b is asserted low. This may just be a side-effect of the prog_b issue or you may be driving it low from the PIC. When you drive the din pin are you using a bit set/clear instruction or writing directly to the I/O port? If the latter, is the prog_b on the same port?
HTH, Gabor
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