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Atmega 2560 - UART0 RX Interrupt not functional

Posted: Sat May 23, 2026 9:31 am
by minolta
Using Flowcode 10, i made a flow which is using interrupt UART0 RX (Channel 1, 19200 baud rate) and a very small macro to save the received serial data in a circular buffer. Microcontroller used is Atmega 2560, board - Mega 2560 Pro.
I realized that the flow is not functional and start to search for the reason.
SendChar/SendString and ReceiveChar/ReceiveString are perfectly functional without using Interrupt.
When i use interrupt no serial data is received.
I suspect that something is wrong in the configuration, when ISR is activated, but i do not know what.

Re: Atmega 2560 - UART0 RX Interrupt not functional

Posted: Sat May 23, 2026 10:40 am
by mnfisher
I would try stripping it back to basics a bit and try just echoing the string received to UART. Channel 1 is connected n to the USB - so it might be worth trying channel 2?

Martin

Re: Atmega 2560 - UART0 RX Interrupt not functional

Posted: Sat May 23, 2026 11:16 am
by minolta
Yes, i should have thought of this. I removed the CH340 from the board (i use ICSP for programming) and now the uart0 line is "free".
Tested and is working with interrupt activated.
Thanks.

Re: Atmega 2560 - UART0 RX Interrupt not functional

Posted: Sat May 23, 2026 5:07 pm
by mnfisher
That would kill it 😂,

Good to hear you are up and running again...