I have followed several of the threads here about getting the additional uarts working on my ngw100.
I have modded both at32ap700x.c and setup.c to add all 4 uarts, and I have now got usart1 (ttyS0), usart2 (ttyS2) and usart3 (ttyS3) all working. :)
But I cannot get usart0 (ttyS1) going. :cry:
The kernel does not hang (as seen on other threads), and I can echo strings (or redirect dmesg) to /dev/ttyS1, but I see nothing on the output pin using a scope.
I have tried changing the TWI / GPIO kernel setting, as well as commenting out the TWI setup line.
I have also removed the LED support from the kernel.
But still no joy.
Can anyone suggest what I might be doing wrong ?
Do I have to change the GPIO registers somehow when using usart0 ? Or should it just work with what I have done ?