I was thinking whether its feasible to use a 8-bit counter with auto-reload to capture the number of peaks detected within 100ms.
You can use a high-speed counter and capture the time of a pulse. After you have captured enough pulses, you know (from the running counter) how long time has passed according to the counter tick frequency and number of ticks.
I see... So I'm using a integrated 16-bit counter with capture... Thanks...