Hello Experts , UART+DMA(with Rx and Tx) MODBUS RTU implementation in STM32F745 controller at 460800 bps ,Can the Tx Rx callback happen when the number of bytes to be received is unsure of at such high baud rate , Can anybody throw some light ?

[SG.4]

How to implement this in UART+ DMA(no polling /or IRQ enabled methods) STM32cubeMX and IDE both?