LPC MicrocontrollersのトピックRe: SCT

SCT

ianbenton — Fri, 21 Sep 2018 13:48:20 GMT

There is only one connection between SCT1 and SCT0, but I need two. I presume it is possible to output SCT1 on to one of the SCT0 input pins using the switch matrix.

Does this also work if the pin in question is not physically implemented? For instance, SCT0 has an input on PIO0_30, which is not present on the 48-pin version.

Re: SCT

soledad — Wed, 07 Nov 2018 13:14:42 GMT

Hi,

It is an interesting use case... And it is possible to work for your idea.

Regards

Soledad

Re: SCT

soledad — Wed, 21 Nov 2018 13:32:35 GMT

It is an interesting case. But I recommend another way to achieve this.

We can use the SCTIPU abort module, as shown below.

We can choose the SCT0_OUT9 to be a abort source, as shown below and use the output SCTIPU_ABORT1 as the SCT1 input.

Details can be found in the relevant sections of UM:

Chapter 9: LPC15xx Input multiplexing (INPUT MUX);
Chapter 14: LPC15xx SCT Input Processing Unit (SCTIPU);
Chapter 15: Large SCTimer/PWM (SCTimer0/PWM,SCTimer1/PWM).

Regards

Soledad

Re: SCT

ianbenton — Wed, 21 Nov 2018 16:12:04 GMT

That's smart! Unfortunately, the original idea for which I needed the connection didn't work. (Hoping to measure the relative phase of mains current by detecting zero-crossing, but the current waveform was so non-sinusoidal that it didn't work). I'll remember it in case I need it again.