AnsweredAssumed Answered

UART block transfer issues

Question asked by Martin.Pablo.004 on Apr 17, 2017
Latest reply on Apr 18, 2017 by howard n2wx

Hi all,

I am having some issues using the UART of an STM32F446RE (in a Nucleo board). I am pretty much a newbie so this might come as a very basic question.

All I intend to do is to transfer data from SRAM to an external PC using UART. I am using CubeMX to generate the initialization code and am using Embedded Workbench.

The problem seems to be that I am unable to write in the Data Register of the UART. While debugging I can see the control registers for the UART are configured as I would expect, but the bits TC and TXE seem to be always set in the Status Register.

I tried to clear these by software; I can clear the TC bit but it sets back automatically when I attempt to write data in the data register. I cannot clear the TXE. According to the reference manual, this should be cleared automatically when writing data to the Data register, but this doesn't seem to be happening. Nothing actually seems to be happening when writing data to the DR.

Also worth of mention, I connected an oscilloscope (I dont have a logic analyser) to the Tx line to see if there is actually something is happening that cannot be seen in the registers during debugging, but that's not the case... all I see is the pull-up voltage..


Am I missing something?


Thank you very much in advance.