Why the maximum value of Tim4Encoder is 127 rather than 32767?

[SYoun.1]

int16_t GetTim4Encoder(){
    Tim4Encoder = __HAL_TIM_GET_COUNTER(&htim4);
    //__HAL_TIM_SET_COUNTER(&htim4,0);
    return Tim4Encoder;
}

[waclawek.jan]

What's the value of other TIM4 registers, mainly TIM4_ARR?

JW

[SYoun.1]

Thank you for answering the question. I am a beginner of STM32 so I know little about the registers. This is SerialPrint() function.

void SerialPrint(uint32_t Tx){
	if(Tx == 0){
		TxMessages[0] = '0';
		HAL_UART_Transmit(&huart1 ,(uint8_t*)&TxMessages, 1, 0xFFFF);
	}
	else{
		tmp = abs(Tx);
		j = 0;
		length = 0;
		while(tmp != 0){
			TxMessagesTmp[j++] = tmp%10 + '0';
			tmp /= 10;
			length++;
		}
		if(Tx > 0){
			for(j = 0;j < length;j++){
				TxMessages[j] = TxMessagesTmp[length-j-1];
			}
			HAL_UART_Transmit(&huart1 ,(uint8_t*)&TxMessages, length, 0xFFFF);
		}
		else if(Tx < 0){
			TxMessages[0] = '-';
			for(j = 1;j < length + 1;j++){
				TxMessages[j] = TxMessagesTmp[length-j];
			}
			HAL_UART_Transmit(&huart1 ,(uint8_t*)&TxMessages, length + 1, 0xFFFF);
		}
	}
	HAL_UART_Transmit(&huart1 ,(uint8_t*)&Apart, 1, 0xFFFF);  //sizeof(TxMessages) has a problem
}

And this is main()

while (1)
  {
    /* USER CODE END WHILE */
 
    /* USER CODE BEGIN 3 */
	  SerialPrint(TIM4->ARR);
          HAL_UART_Transmit(&huart1 ,(uint8_t*)&Apart1, 2, 0xFFFF);
	  HAL_Delay(500);
  }

The value of ARR is pretty strange.

[waclawek.jan]

hummm

Maybe try some other means of printout, or simplify your program to do nothing else just print TIM4->ARR?

Or, perhaps you may try to set up some in-circuit debugging, to observe the registers more directly.

JW

[turboscrew]

Yep. Note, that you can't have negative number to print: SerialPrint(uint32_t Tx). Uint can't be negative.

And you might want to send 0x0D, 0x0A (='\r', '\n' = return, line feed) instead of the underscores?

(I guess the 'Apart' contains underscores.)

Maybe even print some string before the entity to tell what is what?

HAL_UART_Transmit(&huart1 ,(uint8_t*)"\r\nARR: ", 7, 0xFFFF);

SerialPrint(TIM4->ARR);

HAL_UART_Transmit(&huart1 ,(uint8_t*)"\r\n", 2, 0xFFFF);

[SYoun.1]

OK, I will try it. I am just confused about the relationship between this issue and ARR. In other word, after I can observe the registers, how can I solve the problem?

[turboscrew]

You could also initialize the ARR to 65535 and see if that makes the difference.

If you are using CubeMX, do it there.

[SYoun.1]

Apart is '_' to separate data from each send. SerialPrint(...) used to be SerialPrint(uint16_t Tx) but I changed to uint32 to print the ARR.

[SYoun.1]

Thank you, I will try it.

[turboscrew]

To have negative values, it should be int16 or int32.