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HAL_UART_Transmit_IT pauses during transmission

Question asked by Lucas C on Jul 28, 2017
Latest reply on Jul 28, 2017 by Clive One

Hi everyone,


This is not a very serious issue for my application, however, I would like to understand this behavior.

In my application, when the STM receives a packet, it sends out a packet with a confirmation. The content of the packets is not important. What matters is that sometimes the transmission of the packet, in this case, 6 bytes, is paused. As you can see in the images, it transmits 5 bytes, then pauses for about 22ms and then transmits the last byte.

This shouldn't happen as I called the function HAL_UART_Transmit_IT() passing the array with the 6 bytes to be written at once. They should be all transmitted together.


Does any one know what could cause this delay?


I'm using an STM32F030R8 and, according to the header in my code, it should be HAL lib version 1.4.


Overall view. Ch2 is the response byte that suffers the pauseZoom of the first 5 bytes of the response packetZoom of the last 1 byte of the response packet