03-16-2016 04:02 AM
I tried using the test pattern generator (with a VDMA) without success, so I tried simulating it. Somehow, the TPG doesn't seem to do much and I'm not sure if it's a problem with the simultation or with the setup. But if I'm driving the inputs right, the output should work anyway, no matter what's connected to it. aclk runs on 16MHz, the rest of the setup and the simulation is in the pictures below. I ran the simulation for ~110ms, but nothing happened.
03-16-2016 07:00 AM - edited 03-16-2016 07:01 AM
It is working right, the downstream module (or your TB) is just throttling it :).
Set tready to 1.
03-16-2016 09:19 AM
Yes, you're right, I missed that. If I force it to a constant 1, it seems to work just fine. Nonetheless, I routed tuser, tlast and tready to an I/O. tlast and tready look ok, but tuser goes never high. That's probably the reason the VDMA gives me a SOFLate error. In the simulation, tuser works.
03-16-2016 09:24 AM
Tuser only goes high for 1 clock cycle per frame, so it won't light an LED for very long. Have you tried inserting an ILA and triggering in tuser? Or latching tuser to the LED?
03-16-2016 10:05 AM
I measured it with an oscilloscope, that shouldn't be the problem. I can also measure tlast just fine and I think that's also active for just one cycle.