Design question - sampling a relatively low frequency protocol

greycon
Posts: 33
Joined: Fri Nov 03, 2023 9:59 pm

Design question - sampling a relatively low frequency protocol

Postby greycon » Sat Nov 09, 2024 7:40 pm

Hi,
I need to sample and decode a proprietary protocol. It consists of packets arriving at about 700 bits/ Second, and I will need to capture pulses about 500 uS in duration. (Either a single High pulse, 2 High pulses , or 4 High pulses.)

I will likely use an ESP32-C6, running at 160Mhz. (I want to bridge this protocol to Zigbee, thus the C6)

My initial thoughts are to use an edge-triggered interrupt on a GPIO pin, and on the rising edge, start a GP Timer. Then on the falling edge, stop the timer, and write the pulse width to an RTOS Queue, for later handling by an RTOS thread.

Given the pulse width, I think that the ISR latency will not be a factor here.

Any of you more more experienced folk have any thoughts here? Is this a reasonable approach?

Thanks,
Con

MicroController
Posts: 1729
Joined: Mon Oct 17, 2022 7:38 pm
Location: Europe, Germany

Re: Design question - sampling a relatively low frequency protocol

Postby MicroController » Sat Nov 09, 2024 10:31 pm

500us on average shouldn't be a problem for GPIO interrupts. The question is where is the information hidden in that protocol? Do you need to measure the pulse widths? To what accuracy? Or do you only need to count pulses per time interval?
The Pulse Counter or the RMT may be worth looking into.

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