HAL_transmit in other fils (no main.c)

[jlecl.1]

Hello,

I'm trying to send data over uart from a another file.

My main :

UART_HandleTypeDef huart1;
DMA_HandleTypeDef hdma_usart1_tx;
 
int main(void)
{
     MX_USART1_UART_Init();
 
     While(1)
     {
     }
}

My error is :

../Core/Src/AT_Command.c:22:21: error: 'huart1' undeclared (first use in this function)

I'have read that a must declare "UART_HandleTypeDef" as extern...

but i'no unsterdant how.

do you have more information ?

[Winfred LU · Accepted solution]

Declaring it (the global variable) extern is required

because the variable is declared in another file (that can be accessed) in the program.

They are in different scope.

[jlecl.1]

Ok, i have found !

So in your main

extern UART_HandleTypeDef huart1;

instead of "UART_HandleTypeDef huart1; "

AND in your other file, add

UART_HandleTypeDef huart1;