My stm32 board has four uart ports. Each of them is connected to rs 485 transmitter (tx only).
I'm looking for any ideas how to extend my project to have more than four uart ports - up to 10.
My first idea was to connect from my main stm32 board to many smaller stm32 boards over spi (one small board = one rs485) but I'm afraid of synchronization - i need to send all data to rs485 at the same time.
Do you have any other ideas?
I will be grateful for any ideas.