Associate III

Question

STM32F407 Buffer printing HAL_UART_Transmit

Forum|Forum|2 years ago
October 23, 2023
16 replies
6006 views

Good morning everyone, after collecting some data and storing it in various buffers, I am trying to write them to the serial port for further processing. I am experiencing issues as I can see that something is being written to the serial port, but not all the samples in the buffer are being printed. Any suggestions?

while (1)

{

HAL_UART_Receive (&huart2, UART1_rxBuffer, 1, 5000); //receive and store string

if(UART1_rxBuffer[0] == 115){

HAL_UART_Transmit(&huart2, UART1_rxBuffer, 1, 100); //print received string

if(flag == 1){ //check add finished

for(c=0;c<ADC_BUF_SIZE/2;c++){

sprintf(str, "%hu",(uint16_t*)buf1[c]); // conversion in str of value

HAL_UART_Transmit(&huart2, (uint8_t*)str, strlen(str), HAL_MAX_DELAY);

HAL_Delay(10);

}

HAL_UART_Transmit(&huart2,(uint8_t *)space,strlen(space),10); // string = “— — — — ;”

UART1_rxBuffer[0]=0; // start flag clear

flag = 0; // conversion adc clear

}

STM32F4 series

This topic has been closed for replies.

TDK

Check to ensure you can shift out data at least as fast as it's coming in. If you ADC capture rate is above what you can send out, you will lose data.

If you're unsure how to do that, give more information on your capture rate.

> ADC_BUF_SIZE/2

Curious that you're only going up to half of the buffer. Could be correct, might not be. It's impossible to say without seeing more code.

> (uint16_t*)buf1[c]

Careful of order of operations here. You probably want ((uint16_t*)buf1)[c].

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D

davidecAuthor

Associate III

I have modified the ADC clock to 72 MHz. Once the data is sampled (as indicated by the flag), it enters the while loop and should print the values stored in the buffer. The reason ADC_BUF_SIZE/2 is used is that I am storing the data in a 32-bit buffer and then splitting the values into two variables.

D

davidecAuthor

Associate III

I am debugging and the values are written correctly but the problem is that I do not see them on the serial and if I do see them it is sporadic

Karl Yamashita

Principal

Use code formatting so it is easier to read the code

Screenshot 2023-10-23 091035.png

while (1)
{
	HAL_UART_Receive(&huart2, UART1_rxBuffer, 1, 5000); //receive and store string
	if (UART1_rxBuffer[0] == 115) {
		HAL_UART_Transmit(&huart2, UART1_rxBuffer, 1, 100); //print received string
		if (flag == 1) { //check add finished
			for (c = 0; c < ADC_BUF_SIZE / 2; c++) {
				sprintf(str, "%hu", (uint16_t*) buf1[c]); // conversion in str of value
				HAL_UART_Transmit(&huart2, (uint8_t*) str, strlen(str),
						HAL_MAX_DELAY);
				HAL_Delay(10);
			}
			HAL_UART_Transmit(&huart2, (uint8_t*) space, strlen(space), 10); // string = “— — — — ;”
			UART1_rxBuffer[0] = 0; // start flag clear
			flag = 0; // conversion adc clear

		}
	}
}

What do you see in your buf1 and what is being printed?

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davidecAuthor

Associate III

in buf1 I see the values I would like and I also see the counter running in debug, the problem is that in order to analyse the data I have to print them out on the serial, but the values are printed out sometimes or not at all.

Karl Yamashita

Principal

You've mentioned you have a 32 bit buffer which I assume is buf1? So does that mean there are 2 ADC (16bit) values saved in each index? If so, and I assume you want to print each 16bit value one at time with a 10ms delay, you'll need to send the lower 16bits, then the upper 16 bits by bit shifting .

for(c=0;c<ADC_BUF_SIZE;c++)
{

 sprintf(str, "%hu",(uint16_t*)buf1[c]); // conversion in str of value

 HAL_UART_Transmit(&huart2, (uint8_t*)str, strlen(str), HAL_MAX_DELAY);

 HAL_Delay(10);

 sprintf(str, "%hu",(uint16_t*)(buf1[c] >> 16)); 

 HAL_UART_Transmit(&huart2, (uint8_t*)str, strlen(str), HAL_MAX_DELAY);

 HAL_Delay(10);

}

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davidecAuthor

Associate III

i have already done it. The adc sample the signal that i need and after the buffer filling I need, it does not change buf1 and buf2. The problem remains for me to print the values to serial and then process them externally.

for(i=0;i<ADC_BUF_SIZE/2;i++)

			 	 {
			 		 buf1[i] = (uint16_t)(adcBuf[i]&0x0000FFFF);
			 	 	 buf2[i] = (uint16_t)(adcBuf[i]>>16);
			 	 }
	}

Tesla DeLorean

Guru

Would seem like it should mostly work. Might need to clear the UART of overrun, or other errors, and it's not going to receiver and transmit concurrently with blocking functions.

I'd probably write to a buffer, and service with an interrupt until empty. Not a fan of the HAL implementation.

Would likely separate the numbers output so each is distinguishable. Also side effect of sprintf() is to report the string length.

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davidecAuthor

Associate III

Screenshot 2023-10-24 alle 11.02.56.png

Karl Yamashita

Principal

So what interface are you using to communicate with uart2? I suspect that is your weak link.

I am using a STM32F407VG-Discovery, used your code and saved the same data that you've provided. When i press the letter 's', I am able to output all the data correctly.

Screenshot 2023-10-24 025636.png Screenshot 2023-10-24 025645.png

If a reply has proven helpful, click on Accept as Solution so that it'll show at top of the post.CAN Jammer an open source CAN bus hacking toolCANableV3 Open Source

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davidecAuthor

Associate III

I am using a TTL converter because via usb I cannot see the serial port. Is there some setting I'm missing?

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