we are using from years a LPC1788 module with 120MHz CPU frequency and 60Mhz EMC frequency (32bit SDRAM and NOR FLASH) starting from a quartz 12Mhz. The implemented applications work well, we have more products that use panels with resolutions up to 800x600, communications bus, analog and digital I/O, ecc...
Now we would like consider using 84Mhz for CPU and EMC, we want increase the system performance but also maintaining the robust and reliable system.
We already tested the 96MHz but with complex applications get of HARD FAULT.
The 84Mhz tests are satisfactory pier and everything seems to work.
We know that we are going beyond the specification limit of 80Mhz for EMC. We would like to avoid changing the 12 MHz crystal to 16Mhz for the optimal frequency of 80MHz.
Do you think going 4 MHz more than the allowed limit could give problems that now we do not see? Does anyone already use the system in this way?