What happens when the STM32 serial port sends 0 when powered on?

djy243

What happens when the STM32 serial port sends 0 when powered on? [Copy link]

                                 Why does the STM32 serial port send 0 by default when powered on?

fujike029

                                 It seems to be related to the initialization of the TX pin of the STM32 serial port.

erlangzhou

Why does the STM32 serial port send 0 by default when powered on?

It is impossible for the STM32 to send anything by default on the serial port after power-on. There must be something wrong with your initialization program.

saqi99

#include"main.h"

void Sys_init(void)
{
//RCC_Configuration() ; /*Clock setting */
//NVIC_Configuration(); /*Interrupt vector setting */
/*Port setting */
//UART4_Configuration(); /*Serial port 4 setting */
//UART5_Configuration(); /*Serial port 5 setting */
//GPIO_Configuration();
//TIM1_Configuration();
//TIM8_Configuration(0); /*Timer 8 setting */
}
int main(void)
{

//Sys_init(); //System initialization
//GPIO_ResetBits(GPIOB, GPIO_Pin_13); //Driver low level DIR turns clockwise
//GPIO_ResetBits(GPIOB, GPIO_Pin_14);//Driver high level FREE
//TIM_Cmd(TIM1, ENABLE); //Start timer 1
while(1)
{

}
}
Do not do any initialization

zhaowo

Without any initialization, it is like this after powering on several times

Screenshot00.png (25.01 KB)

Downloads:0

2010-3-30 17:25

james0758

Please use an oscilloscope to measure the level of the STM32 TX pin. I strongly suspect that this problem is caused by other devices on your circuit board, such as the RS232 conversion chip.

The I/O pins of the STM32 are in high-impedance state after reset and cannot be recognized as 0 unless the chip is damaged.

dm29769671

                                 If it is not an initialization problem, it is likely caused by a hardware problem

zhaonaiqiang

                                 It should be a hardware problem. I have encountered it before.

sen234

                                 It should be a hardware problem