PlatformIO Community

Attiny two HW UART integration (Attiny 1624)

Hello everybody,

i need your help.

A friend and i creating a little project (little Blocks for kids with some functions and kommunication between the blocks) with a Attiny1624. This controller has two hardware UARTS and we want to use them to communicate with other Attiny 1624 in a chain.

PlatformIO only supports the Attinys with one UART and currently the only solution is to use the Arduino IDE to programm the 1624, beacuse of the megaTinyCore . This Arduino Board was integratet in 2019 or so in PlatformIO, but without the two HW UART chips.

Can anybody help me to solve this?
The usage of the Arduino IDE is a pain.
I already tried to contact Ivan Kravets, but they have no time to support the chips as a Open Source project.

Greetings from Germany

Open Issues on GitHub

Suppport for ATTINY1624 · Issue #263 · platformio/platform-atmelavr (

Hi Marco

I am not an expert but was able to get this working with the 1624 and the two UARTS. I am hazy now on how I did this but I recall I created and/or edited the iotny1614 pin definition file. I went back to my simple test routine and it still compiles! Maybe I can help you with this if you let me know how far you have progressed.


I’ll add support shortly and update the issue for people to test it. (I don’t have the hardware)

I’ve updated the issue.