improved reading from sensor and fixed a few bugs

Author: git-user-cpp

Core/Inc/AHT20.h

@@ -61,7 +61,7 @@ aht20_status_t aht20_calibrate(I2C_HandleTypeDef *hi2c, uint8_t status_word);
  * Datasheet: AHT20 Product manuals
  * 5.4 Sensor reading process, paragraph 2
  */
-aht20_status_t aht20_measure(I2C_HandleTypeDef *hi2c, uint8_t *measured_data);
+aht20_status_t aht20_measure(I2C_HandleTypeDef *hi2c, uint8_t *measured_data, uint16_t measured_data_size);
 
 /*
  * resets the sensor without turning off the power supply

Core/Src/AHT20.c

@@ -119,32 +119,22 @@ aht20_status_t aht20_calibrate(I2C_HandleTypeDef *hi2c, uint8_t status_word) {
  * Datasheet: AHT20 Product manuals
  * 5.4 Sensor reading process, paragraph 2
  */
-aht20_status_t aht20_measure(I2C_HandleTypeDef *hi2c, uint8_t *measured_data) {
-	uint8_t received_crc = 0;
-
+aht20_status_t aht20_measure(I2C_HandleTypeDef *hi2c, uint8_t *measured_data, uint16_t measured_data_size) {
 	if (HAL_OK != HAL_I2C_Master_Transmit(hi2c, DEVICE_ADDRESS, MEASURE_CMD, (uint16_t)sizeof(MEASURE_CMD), HAL_MAX_DELAY)) {
 		return AHT20_STATUS_NOT_TRANSMITTED;
 	}
 	HAL_Delay(80);
 
-	uint8_t measuring_status = 0;
-	HAL_I2C_Master_Receive(hi2c, DEVICE_ADDRESS, &measuring_status, (uint16_t)sizeof(measuring_status), HAL_MAX_DELAY);
-
-	uint8_t all_data[7];
-	if (measuring_status & (1 << 7)) {
-		return AHT20_STATUS_NOT_MEASURED;
-	} else {
-		HAL_I2C_Master_Receive(hi2c, DEVICE_ADDRESS, all_data, (uint16_t)sizeof(all_data), HAL_MAX_DELAY);
+	if (HAL_OK != HAL_I2C_Master_Receive(hi2c, DEVICE_ADDRESS, measured_data, measured_data_size, HAL_MAX_DELAY)) {
+		return AHT20_STATUS_NOT_RECEIVED;
 	}
 
-	// Copy 6 data bytes to measured_data
-	for (uint8_t i = 0; i < 6; ++i) {
-		measured_data[i] = all_data[i];
+	if (measured_data[0] & (1 << 7)) {
+		return AHT20_STATUS_NOT_MEASURED;
 	}
-	received_crc = all_data[6]; // CRC is the 7th byte
 
-	uint8_t calculated_crc = calculate_crc(measured_data);
-	if (calculated_crc == received_crc) {
+	uint8_t calculated_crc = calculate_crc(measured_data + 1);
+	if (calculated_crc == measured_data[0]) {
 		uint8_t ack = 0x06;
 		if (HAL_OK != HAL_I2C_Master_Transmit(hi2c, DEVICE_ADDRESS, &ack, (uint16_t)sizeof(ack), HAL_MAX_DELAY)) {
 			return AHT20_STATUS_NOT_TRANSMITTED;

Core/Src/main.c

@@ -89,7 +89,7 @@ void print_error(aht20_status_t status) {
 		/* doing nothing if ok */
 	}
 	else {
-		printf(debug_msg, "Unknown error\r\n");
+		sprintf(debug_msg, "Unknown error\r\n");
 		UART_Send_String(debug_msg);
 	}
 }
@@ -167,18 +167,19 @@ int main(void)
 
 	/* Infinite loop */
 	/* USER CODE BEGIN WHILE */
-	uint8_t measured_data[6] = {0};
+	uint8_t measured_data[7] = {0};
 	float humidity = 0.0;
 	float temperature_c = 0.0;
 	float temperature_f = 0.0;
 
 	while (1)
 	{
 		/* triggering measuring */
-		status = aht20_measure(&hi2c1, measured_data);
+		status = aht20_measure(&hi2c1, measured_data, (uint16_t)sizeof(measured_data));
 		if (status != AHT20_STATUS_OK) {
 			print_error(status);
-			return 3;
+			aht20_soft_reset(&hi2c1);
+			continue;
 		}
 
 		aht20_calculate_measurments(measured_data, &humidity, &temperature_c, &temperature_f);