STM32F071, USART1, TXE/TC bits in ISR register not set...

[JuM]

Posted on May 09, 2018 at 14:49

Try to send 16 bytes via USART1.

ISR has reset value (0xnnnn n0C0) before sending first byte.

Write bytes into TDR like this: USART1->TDR = *bufptr++;

ISR bits TXE and TC get cleared as expected (0xnnnn n000) after first byte.

But neither TXE not TC get set again !?!

So cannot send the remaining 14 bytes...

What can cause this?

[waclawek.jan]

Posted on May 15, 2018 at 18:46

Transmitter and/or UART not enabled?

Handshake enabled and active?

Read out and check/post other UART registers content.

JW

[Tesla DeLorean]

Posted on May 16, 2018 at 00:23

Provide an example that illustrates the problem fully. If you are probing the USART registers in the debugger, stop doing so.

Check for error flagging.