Posted on December 04, 2017 at 18:21 Hello ..
I am having a very weird issue with my code piece ..
The MCU is STM32F407VET6 .. What I'm trying to do is sending a string via USART1 peripheral module .. In order check if the character in the USART1 is sent out of the USART1->DR register I am continuously checking the 'Transmit Complete Bit of the usart1 status register
The code below works well ...
TC1 is defined as USART1_SR_TC register bitband alias ...
#define TC1 *((uint32_t *)(0x42220018)) //Previously defined at the top of the main file
void EXTI4_IRQHandler(void)
{
uint8_t i;
char x[6]='BURAK\n';
EXTI_PR_Bit4=1; // Cleared by writing 1
// ISR code
TC1=0;
for(i=0;i<7;i++)
{
USART1->DR=x[i];
while(!(USART1->SR&USART_SR_TC));// Transmit Complete ?
}
TC1=0;
}
BUT !
When I replace
while(!(USART1->SR&USART_SR_TC));
with
while(TC1==0);
The code stucks.. freezes ... and stops ...Why does it happen ?? Are Bit-Band Aliases not reliable things to use with while ,if , for statements ?? Does it have to be read/modify/write sequence always ??
Thanks in advance ..
#flag-check #bitband #while #stuck
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