我正在使用 STM32F4 发现板 - http://www.st.com/st-web-ui/static/active/en/resource/technical/document/data_brief/DM00037955.pdf
我正在尝试使用 ST Micro STLink 软件中的串行线查看器通过类似“printf”的语句进行调试：http: //www.st.com/st-web-ui/static/active/en/resource/technical /document/user_manual/CD00262073.pdf
但是，尽管将系统时钟设置为 168000000 Hz 并将激励端口设置为“全部”，但我在 SWO 查看器中看不到任何结果。我在芯片上运行的（相关）软件如下。此演示设置为根据按下用户按钮更改 LED 灯。
static uint8_t lastButtonStatus = RESET;
int main() {
init();
do {
loop();
} while (1);
}
void init() {
initLeds();
initButton();
}
void loop() {
static uint32_t counter = 0;
uint8_t currentButtonStatus = GPIO_ReadInputDataBit(GPIOA, USER_BUTTON);
if (lastButtonStatus != currentButtonStatus
&& currentButtonStatus != RESET) {
++counter;
GPIO_ResetBits(GPIOD, LEDS);
GPIO_SetBits(GPIOD, LED[counter % 4]);
// Test SWD output
SWV_puts("hello from stm32f4\n");
SWV_printfloat(1.98254, 2);
}
lastButtonStatus = currentButtonStatus;
}
以下是SWV_打印功能：
void SWV_puts(const char *s )
{
while (*s) ITM_SendChar(*s++);
}
/**
* @brief This function sends numbers to the serial wire viewer.
* @param number: number to be displayed on SWV
* @retval None
*/
void SWV_printnum(long number)
{
unsigned char buf[8 * sizeof(long)]; // Assumes 8-bit chars.
unsigned int i = 0;
//if number is 0
if (number == 0)
{
ITM_SendChar('0'); //if number is zero
return;
}
//account for negative numbers
if (number < 0)
{
ITM_SendChar('-');
number = number * -1;
}
while(number > 0)
{
buf[i++] = number % 10; //display in base 10
number = number / 10;
//NOTE: the effect of i++ means that the i variable will be at number of digits + 1
}
for(; i > 0; i--)
{
ITM_SendChar((char)('0' + buf[i-1]));
}
}
/**
* @brief This function sends numbers to the serial wire viewer.
* @param number: number to be displayed on SWV
* @param digits: number of digits after decimal point
* @retval None
*/
void SWV_printfloat(double number, int digits)
{
int i = 0;
//handle negative numbers
if(number < 0.0)
{
ITM_SendChar('-');
number = -number;
}
//round correctly so that uart_printfloat(1.999, 2) shows as "2.00"
double rounding = 0.5;
for(i = 0; i < digits; ++i) rounding = rounding / 10.0;
number = number + rounding;
//extract the integer part of the number and print it
unsigned long int_part = (unsigned long) number;
double remainder = (double)(number - (double)int_part);
SWV_printnum(int_part); //print the integer part
if(digits > 0) ITM_SendChar('.'); //print decimal pint
int toprint;
while(digits-- > 0)
{
remainder = remainder * 10.0;
toprint = (int)remainder;
SWV_printnum(toprint);
remainder = remainder - toprint;
}
}
我可以确认代码编译时没有错误或警告感谢您帮助我进行 SWD 打印，以便我可以调试实际程序 =)
