Missing last bit of UART transmit about debugdonglefw HOT 3 CLOSED

So my analysis may be wrong. But what is really strange is that if I tie together RX and TX, the output on putty is correct, i.e. when I type U I receive U. This is what I get on Tx @ 115200bps

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The __WFI() command only stops the processor clocking, peripherals are unaffected by default. USART_eTransmit_DMA() - unlike USART_eSend_DMA() - indeed doesn't check for TC flag at the end of the transfer, and returns as soon as the last byte is transferred to the USART peripheral and it's transmission begins. However, consecutive USART_eTransmit_DMA() calls will wait for TXE flag before writing to the peripheral.
That being said, I could also observe the same behavior. After some investigation I figured out the problem: the USART word length was incorrectly configured. That is why 'U' was looped back correctly - 0xAA however would end up as 0x2A. The specific error was this line in xpd_usart.c:
uint8_t ucFrameSize = ucDataSize + (eParity != USART_PARITY_NONE) ? 1 : 0;
ucFrameSize was 1, as the ? operator apparently doesn't have precedence over the + operator.
The line should look like this:
uint8_t ucFrameSize = ucDataSize + ((eParity != USART_PARITY_NONE) ? 1 : 0);

This error is corrected on STM32_XPD master, please check on your side that the UART characters are as expected.

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Thank you for the quick and great support !
The VCP works flawlessly now.

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