Minimum pulse width for input capture using timers

lpcware — Wed, 15 Jun 2016 21:47:10 GMT

Content originally posted in LPCWare by kevink on Tue Jul 06 11:01:57 MST 2010
Hi,

I cannot seem to find in the datasheet or usermanual for the LPC11xxs the minimum required pulse width for the input capture of the 16/32 bit timer 1/0 modules to be able to 'see' an external event (or for general purpose external interrupt sources).

Example: I need to time how far apart two 40ns pulses are (the line is low, then goes high for 40ns, then goes low again, and repeats).

What is the minimum required pulse width? Is [B]40ns long enough?[/B]

In the user manual under the counter section for the timers it says the frequency needs to be at least half of the [B]PCLK[/B] (to satisfy Nyquist). It also says the period cannot be shorter than [B]1/(2*PCLK)[/B] but I think that is a typo, It should be no shorter than [B]2/PCLK[/B] right? Is this true for just random pulses using the input capture part as well?

Any help would be great, Thanks.

topic Minimum pulse width for input capture using timers in LPCXpresso IDE

Minimum pulse width for input capture using timers