I’m using XEM3010-1500 and there are some weird problem associated digital output pins. So I have 16 pins (xbus) configured as digital output pin, signal frequency is around 10MHz. And I have four modules “Ch1.v, Ch2.v, Ch3.v, and Ch4.v” to specify the output pattern. Each module controls 4 pins. Currently all four modules are exactly the same behavior. But when I download the bit file onto the board, sometimes 4 pins from one module will fail to output the specified waveform. And the failure pins will change if I change the module code a little bit. Basically the failed output pins stops to output data, or miss some transitions.
Does anyone experience similar problems? I want to know what’s wrong with the board. It looks to me like the FPGA chip output driver is not strong enough, or the board wiring is seeing some ringing.