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EVALBOARD STM32L476G USART1 receive problem

Question asked by guillaume.dugast on Jun 1, 2016
Latest reply on Jun 6, 2016 by Clive One
Hello,

I am working on the STM32L476G board, with my own code (except using: stm32l4xx.h, stm32l476xx.h, system_stm32l4xx.h, startup_stm32l476xx.s and core_cm4.h).
Which means that i'm building my own usart driver in this way:
 i.e.:
usart[id].reg->ISR &= ~ USART_ISR_TXE;

I'm trying to have a functionnal RS com through the usart 1 rx and tx pins, with this config:
8bits, even, 1 stop bit, no hw flow control.

I have configured the usart 1 and the transmission works. (tested on an hyperterminal and with an analyzer (scanastudio)).

I have issues trying to get usart 1 reception working (for a couple of days now :/ )
Do you think it can be due to the pinning of the eval board?
Is there any other way I can test it?

What is going on exactly?
- starting programm
- initializing usart1
- then I have an interrupt with ISR.FE, ISR.CMF and ISR.RXNE set
- but, as soon as go to the next instruction (with a JTAG debugger), and,
without doing anything (the line can be __ASM("nop")), the ISR.RXNE is cleared by i-don't-know-who. After this, the RXNE flag is not set anymore.

Thank you for your time and sorry for the bad english.

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