There are several microcontroller architectures within the Arduino family officially as well as compatible ones that are also called Arduino-something.
The classic (and oldest) are the AVR microcontrollers (ATmega), which are not supported by embassy nor rtic at the moment AFAIK.
They are supported by Rust, though. see: https://github.com/rahix/avr-hal.
However, there are several other Arduino microcontrollers that are supported. For example the Arduino Nano RP2040, Arduino Nano 33 BLE (nRF), the Arduino MKR ones as well as the STM32duino (STM32F103, the one in the hugely popular $2 blue-pill boards) are all based on the ARM cortex-m architecture, which is supported by both embassy as well as rtic.
The classic (and oldest) are the AVR microcontrollers (ATmega), which are not supported by embassy nor rtic at the moment AFAIK. They are supported by Rust, though. see: https://github.com/rahix/avr-hal.
However, there are several other Arduino microcontrollers that are supported. For example the Arduino Nano RP2040, Arduino Nano 33 BLE (nRF), the Arduino MKR ones as well as the STM32duino (STM32F103, the one in the hugely popular $2 blue-pill boards) are all based on the ARM cortex-m architecture, which is supported by both embassy as well as rtic.
For espressif chips (like the esp32), support is being worked on by the manufacturer itself: https://github.com/embassy-rs/embassy/issues/745
Here an overview of microcontrollers in the (official) Arduino family: https://www.makeuseof.com/exploring-different-types-of-ardui...