Support for multiple UARTs at same time?

[krdarrah]

Great project! But curious if possible to support multiple UARTs at the same time, so two hosts have ability to upload? I'm specifically working on the ATMEGA2560 and would like to upload from USB-Serial or BT-Serial on UART0/1

[MCUdude]

Sorry for the incredibly slow response!
The pre-compiled bootloaders that are bundled with MegaCore do not support multiple UARTs at the same time. However, The urboot bootloader is highly configurable, so there might be hope. Would this be possible @stefanrueger?

[stefanrueger]

Not two USARTs at the same time: I am not even sure how the bootloader would know which USART to listen to after reset. Poll both RX lines and then use the one that rears its head first? Check out a certain pin and select one USART if high and the other one if low?

Anyway, this looks like a bespoke application for which a bespoke bootloader would be needed.

Urboot specialises in small code size, so its not likely that a feature request like this would be implemented even if offered as PR.