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UART transmitting in Interrupt mode vs. DMA mode

Question asked by Daniel Studer on Jun 15, 2017
Latest reply on Jun 15, 2017 by waclawek.jan



I'm working with an STM32F7xx with the Cube HAL library. Im using the UART and I tried all 3 transmitting functions of UART. These are HAL_UART_Transmit, HAL_UART_Transmit_IT and HAL_UART_Transmit_DMA. all 3 methods are working well. But I dont't really understand the difference between the Interrupt and DMA method.


In Interrupt method I just give a pointer to my sending data to the function as same with the DMA function. In debugging mode I see that the Interrupt function is doing less code than the DMA function. My question now is, is the processor executing more code in interrupt mode than in DMA mode after these functions are called? I can't see that the processor is  executing more in Interrupt mode. I thought with DMA the processor is less involved than without DMA.


Thanks for helping.


Best regards,