Using RMT as UART (IDFGH-8682)

[StarOfSlytherin]

Is your feature request related to a problem?

My application requires 5 UART ports. So I have a shortage of Hardware UART ports, Software UART would be helpful in my situation. I know software UART will have issues in high baud rate scenarios but my use case is 4800 & 9600 on software UART.

I found a library on using RMT as UART but it has a few drawbacks. The most important for me is the lack of support for Even parity. Here's the link to the library: https://github.com/naffej/esp32-rmt-uart

I have searched a lot for this and seen a few people looking for this feature on the ESP32 forums, Reddit etc. Hope you consider adding an example or a component as a feature.

Describe the solution you'd like.

A Software Serial component or an example to use RMT as Software UART

Describe alternatives you've considered.

I couldn't find any software solutions but I have considered using a Mux IC to switch multiple serial ports to a single GPIO pin. The issue with this is I'll have to de-init and re-init the UART driver to change the baud rate, parity etc.

Additional context.

No response

[suda-morris]

Thanks for the idea, we will consider adding such an example in the future. Implement the UART protocol via RMT is equivalent to writing an encoder to translate the user buffer into RMT data format. Actually we have already provided many of them (e.g. NEC, One-Wire), hope you can get inspired from them

BTW, in some ESP series (e.g. ESP32C3, ESP32S3), we also provided CPU instructions to manipulate the GPIO, which means you can implement the UART protocol by writing assembly code. We're currently preparing such examples internally.

[StarOfSlytherin]

Thanks for the reply. I'll see if I can write a UART encoder but in any case can I expect the examples with v5.0 release?

[StarOfSlytherin]

I just saw the dedicated GPIO examples. Is it restricted to RISC-V or will there be support for Xtensa CPUs later?