9-BIT UART TRANSMISSION STM32 cubemx hal driver

[Ibrahim Benaddi]

Posted on December 06, 2017 at 18:06

Hello,

I'm using STM32cubemx and I have created a project using UART in 9-bit configuration. The code is generated and I can find the 'HAL_UART_Transmit' function but the pData parameter is a 8-bit pointer:

HAL_StatusTypeDef HAL_UART_Transmit(UART_HandleTypeDef *huart, uint8_t *pData, uint16_t Size, uint32_t Timeout)

pData should be a 16-bit parameter. I cannot understand how can I send a 9-bit data with this function. Is it a bug in STM32CubeMX?

Thanks

IBRA

[Tesla DeLorean · Accepted solution]

Posted on December 06, 2017 at 22:43

No, the byte array is just a universal solution. A 9-bit value is going to be spread over two bytes, low order bits in the first, or just use a 16-bit array and CAST it. The transfer count is in units, to send two 9-bit words, Size = 2

uint16_t x[2] = (0x123,0x091};

HAL_UART_Transmit(huart, (uint8_t *)x, 2, 1000);

[Ibrahim Benaddi]

Posted on December 07, 2017 at 11:39

Clive,

I test successfully this solution 

Thank you for your help.

IBRA

[msingh08]

Hi, 

I've tested your solution and it seems to work fine however it is only sending the data at every other request would you know any other way of setting the 9th bit? I've tried changing the variable type to be uint8_t and the data(wrong)  is sent at every request. 

Kind Regards

Manpreet Singh