[SOLVED] STM32L0 possible bug with DMA

[VLau]

Hey!

I'm trying sending message over UART with DMA with following code and CubeMX configuration (attached pictures)

char welcome[] = "hi!\r\n";
  HAL_UART_Transmit_DMA(&huart2, (uint8_t*) welcome, strlen(welcome));

Nothing else is changed.

MCU doesn't send anything. The "HAL_UART_Transmit_IT" & "HAL_UART_Transmit" functions work.

I'm using NUCLEO-L010, tried exact same configuration with another NUCLEO-F303 board and "HAL_UART_Transmit_DMA" works as expected.

Code doesn't stuck or give any error messages during debug.

What did I miss?

[TDK]

What is the return value from HAL_UART_Transmit_DMA?

Might get an example up and running if you're super stuck.

https://github.com/STMicroelectronics/STM32CubeL0/tree/a7b74aed35ecb7baeadeb16107aa8fddb6823589/Projects/NUCLEO-L011K4/Examples/UART/UART_HyperTerminal_DMA

[VLau · Accepted solution]

Ok, just found the answer.

The order in which modules are initialized matters. DMA initialization followed by USART initialization (I had vice versa). Order can be changed in CubeMX.

/* Private function prototypes -----------------------------------------------*/
void SystemClock_Config(void);
static void MX_GPIO_Init(void);
static void MX_DMA_Init(void);
static void MX_USART2_UART_Init(void);