I'm perusing this tutorial and read this:
Seeking clarity about DMA on STM32F410RB
What isn't clear is why we can't...
Seeking clarity about DMA on STM32F410RB
What isn't clear is why we can't...We cannot use any arbitrary DMA controller. Instead, we need to pick the controller, stream and channel that are connected to the UART2 TX function. This will ensure that the DMA controller will not start transferring another byte until the UART controller is ready to accept it (i.e. has finished physically transmitting the previous one).