We replaced 91F40416 to AT91F40816 which Atmel says is a drop in replacement. We had interfaced TI DSP 5416 via the HPI Bus to AT91F40816 operating at 25MHz, and HPI Bus operating at 50MHz.
With the old part AT91F40416 HPI interface had been working absolutely fine, and with a new part we started observing the problem in the Read Cycle at elevated Temperature (say 40-50 deg C). Do not know why? We captured multiple waveforms monitored HPI_RDY Signal, HPI_INT, HR_W, HCNTL0, HCNTL1 and all the Data Lines.
Modified the following to the software for Number of Wait States in the Write Cycle to 1 and Read Cycle to 5. We saw the error reduced number of times, still not clear for the reason why is it happeneing.