PCIe freezing

If the detector shows trouble even in absence of the host/software doing requests, then you know there is something seriously wrong on the lower level. If these errors are just related to the requests or the associated responses to them, it’s hard to tell who is to blame: The PCIe soft IP or the application behind AST.

When writing to your device, there could be problems with credits only if your model behind AST does not fetch the data. Once you fetch data from the buffer (rx_ready/rx_valid asserted), the credit is automatically returned to the Requester by the PCIe IP. If the IP does not return credit for whatever reason, you can get into trouble with write-only requests as well.

Remaining issues are: Buggy Soft IP, some synthesis defects – maybe constraints, clocking, clock domain crossing – hardware defects on the FPGA board or the motherboard.