fpga spartan 6 io ports are no longer working correctly

Thread Starter

Ahmed Darwish

Joined May 3, 2019
HELLO there,

i have spartan 6 of the familyxlc9 but i am facing a severe problem with it . first i can burn successfully with jtag on it .its power is okay but the problem is whatever code i am burning to it

the io ports values doesn't change always all the pins are zeros except 4 pins that have values between 0.9 and 1.2 and another pin that have 3.3 .although the code is working on xillinx it is a simple code. trying to output ones on all the pins i changed the code to a code that does nothing like the fpga sends the same values on the output pins . i thought that those pins are no longer working

changed to another pins but all are zeros . it is like the output ports keeps a certain previous state and stand still.

i don't know does my fpga fails and has to be changed ? although jtag is burning code successfully

does spi flash memory is not working ? although i tried to upload the code on fpga directly and get the same output

thanks in advance


Joined Jan 12, 2019
May be you have sourced too much current or connected a low impedance load to the output pins. FPGAs have a maximum load driving current limit and crossing the limit might cause the fpga to be impaired permanently. Most probably you have to replace the chip.


Joined Feb 25, 2011
Most problems like this can be diagnosed by
a) simulating the code first
b) working through the warnings and error messages when you synthesised
c) checking with a scope the power supplies
d) realising what you shorted out during testing,
(chips are powered by smoke, when the smoke escapes, they stop working )