STM32F2x documentation bug?

[cube sphere]

Posted on August 07, 2014 at 10:24

Hello ST,

I have found a discrepancy between the documentation of the STM32F2x MCU and the STM32Cube as well as the StdPeriph implemenation.On page 656 of the RM (RM0033_CD00225773, DocID15403 Rev 6) it is said that bits 31:9 of the UART DR have to be kept at reset value. However, both STM32Cube and StdPeriph libraries set these bits to 0 at transmit/send.Does someone from ST can clarify, please.Best regards,sphere #stm32-documentation

[zzdz2]

Posted on August 07, 2014 at 19:40

I'm not from ST but I think you overinterpreted it.

DR should just be written the data to be transmitted, writing a value higher than 0x1ff doesn't make any sense so bits 31:9 are kind of reserved.

[Tesla DeLorean]

Posted on August 07, 2014 at 20:55

This is a PAIR of registers, not memory cell, the register you read is a holding register for in-bound data, the register you write is a different out-bound register. You can't read the out-bound register.