topic Re: lpc8xx SCT timer registers (SCTimer/PWM Cookbook app note) in LPC Microcontrollers

lpc8xx SCT timer registers (SCTimer/PWM Cookbook app note)

topspin — Tue, 25 Jul 2023 08:57:09 GMT

Hi all,

I have a question about the AN11538 app note. can you tell me why at hte beginning of chapter 6.2 seems to use the MATCH register and then in the code of chapter 6.3 it uses the MATCHREL registers? What are the differences between MATCH and MATCHREL?

Thanks

Regards

Re: lpc8xx SCT timer registers (SCTimer/PWM Cookbook app note)

Miguel04 — Wed, 26 Jul 2023 18:34:20 GMT

Hi @topspin

MATCH and MATCHREL are 2 different registers, you can find the information on the user manual (f.e. LPC82x\'s UM10800) chapter 16.6.1.3 Match and capture registers

"The SCT includes a set of registers to store the SCT’s match or capture values. Each
match register is associated with a match reload register which automatically reloads the
match register at the beginning of each counter cycle."

Best Regards, Miguel.

Re: lpc8xx SCT timer registers (SCTimer/PWM Cookbook app note)

topspin — Fri, 28 Jul 2023 12:10:16 GMT

Hi @Miguel04

Ok I see. But why in the configuration code of the app note it does not initialize the MATCH registers? Don't you skip the first iteration of the counter in this way?

Thanks

Best regards

Re: lpc8xx SCT timer registers (SCTimer/PWM Cookbook app note)

Miguel04 — Fri, 28 Jul 2023 18:32:30 GMT

Hi @topspin

Yes apparently the appnote skips the first iteration of the counter, however on the user manual is not specified that both registers have to be configured simultaneously.

I hope this answers your questions.

Best Regards, Miguel.