Posted by dautrevaux on 2016-03-19 13:01

Hi Ben,

First of all you should check that in your project settings at “project >> C/C++ Build >> Settings >> Tool Settings >> MCU GCC Compiler >> Warnings” the “All Warnings (-Wall)” option is checked. This will gives you warnings on potential errors you may have in your code.

Second, there is indeed several problems in your code:

1. You do not need any parentheses in (pData) = ; you can write it simply as pData =
2. pData, as its name implies, should be a pointer to uint8_t data (bytes);
   1. You should declare it as uint8_t *pData;
   2. Then you cannot assign it a byte, you must assign it the address of a byte, by pData = &TheDataItself;
   3. Finally you can pass to HAL_SPI_Transmit either pData or &TheDataItself, both will request HAL to transmit 1 byte of data (value of cnt), located in the TheDataItself variable

uint8_t TheDataItself = 0xFF;
HAL_SPI_Transmit(&hspi2, &TheDataItself, sizeof(TheDataItself), 10); // 10 is the time out value.

Finally, I think you should read one of the numerous C programming courses you can find on the web: whatever it may look like, C is not a simple programming language, especially when going to pointers, and you need some guidance when starting to program in C.

Hope this helps clarifying things,

Bernard (Ac6)