The size of the FIFO varies based on the intent of the FIFO. If the goal is to use the FIFO data for debugging purposes and it is not periodically retrieved, AMD recommends that the FIFO should at least be able to capture a full initialization report and two full error reports. This requires at the minimum a FIFO that is 512 × 8 in size.
If the Diagnostic Scan feature is used, the Monitor Interface provides not only the means to command the IP to perform these scans but also a means to record the type and location of errors if any errors are found. In this use case, the size of the FIFO needs to accommodate N additional error reports where N is the number of the error reports desired to be collected before taking any mitigation action.
If this information is received periodically, the size of the FIFO depends on how often data is retrieved.
In this use case, tie off the inputs of the interface in the following manner to disable any write commands to the controller:
monitor_txfull = 0 or to the FIFO full flag monitor_rxdata = to all 0s monitor_rxempty = 1
See the following figure for a block diagram example of how to connect the Monitor TX Interface to a FIFO for monitoring and debugging.
The monitor port provides more details of the errors it detects including its address location and timestamp. This additional error information is useful to log the SEU events that occur in a system.