DIIS

DevHeads IoT Integration Server•16mo ago•

1 reply

Dtynin

Issue with Command Handling in AVR128DA48 UART Communication

I am using AVR128DA48 microcontroller to control an LED in serial communication. The way I set it up is not complex;
I’m sending ‘ON’ and ‘OFF’ commands from a

python

python

script over

UART

UART

to toggle the LED on the microcontroller. Funny how I am encountering an issue where the first command is ignored, but the second one triggers a response.

Here’s what happens:
- I send ‘ON’ – the microcontroller does not respond.
- I send ‘OFF’ – it responds with ‘LED ON’.
- I send ‘ON’ again !! – it responds with ‘LED OFF’.

It makes me feel like the board is always responding to the previous command, and I don't know why .

Normally I know microcontroller has simple firmware that reads serial data, processes the ‘ON’ or ‘OFF’ commands, toggles the LED accordingly, and sends back a confirmation message like ‘LED ON’ or ‘LED OFF’.

But what could be causing the delay or missed first command that I am facing?

How can I ensure that the board processes the first command correctly and responds immediately?

I made sure to verifying the baud rate and ensuring it matches on both ends as 9600

Even flushing the serial buffer before and after sending commands in the python script.