LPC MicrocontrollersのトピックRe: Bitbash UART on LPC8N04

Bitbash UART on LPC8N04

brentsinger — Thu, 18 May 2023 02:55:27 GMT

Hi, just wanted to see if anyone has a good uart bitbash snippet I could re-use?

Target is LPC8N04, desired baud is 460080. Would be used for Modbus, so messages can get long.

If anyone can point to a good project that is relevant that'd be great too before I get started.

Re: Bitbash UART on LPC8N04

Alice_Yang — Thu, 18 May 2023 08:07:03 GMT

Hello @brentsinger

Sorry there isn't USART module on LPC8N04.

Alice

Re: Bitbash UART on LPC8N04

brentsinger — Fri, 19 May 2023 23:27:20 GMT

Yes I read that.

Which is why I'm going to Bit Bang a uart into it.

Re: Bitbash UART on LPC8N04

Alice_Yang — Mon, 22 May 2023 08:04:30 GMT

Hello @brentsinger

Sorry, as far as I know, there isn't.

Alice

Re: Bitbash UART on LPC8N04

frank_m — Mon, 22 May 2023 09:48:44 GMT

TI used to have so-called "software implementations" for UART and I2C for their MCUs, which use "bit-banging".
Porting this code from one Cortex M to another is not really difficult.

> Target is LPC8N04, desired baud is 460080.

Though this is far too optimistic for a M0+.

I guess you are talking about Modbus RTU.
The only challenge is the inter-message gap, the rest of the protocol is mostly standard UART.
There are plenty of free Modbus implementations, perhaps you can draw inspirations from them, or consider porting one of them.