SENSIRION SCD30 二氧化碳传感器测量数据转换

硬件：Ｎordic nRF52840 SoC, SENSIRION SCD30

软件: Nordic SDK V15.2, Keil V5.23

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SCD30 I2C 读取测量值命令, 0x0300

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参考代码

float	CO2Concentration,realValueOfTemperature,realValueOfHumidity;
uint32_t tempCO2,tempTemp,tempHumi;
uint8_t	buffer[4];
buffer[0] = 0x43;
buffer[1] = 0xDB;
buffer[2] = 0x8C;
buffer[3] = 0x2E;
tempCO2 = (uint32_t) ((((uint32_t)buffer[0]) << 24) | 
			(((uint32_t)buffer[1]) << 16) | 
			(((uint32_t)buffer[2]) << 8) | 
			((uint32_t)buffer[0]));
	
CO2Concentration = * (float *) &tempCO2;
NRF_LOG_INFO("CO2: " NRF_LOG_FLOAT_MARKER " ppm. \r\n", NRF_LOG_FLOAT(CO2Concentration));


buffer[0] = 0x41;
buffer[1] = 0xD9;
buffer[2] = 0xE7;
buffer[3] = 0xFF;
tempTemp = (uint32_t) ((((uint32_t)buffer[0]) << 24) | 
			(((uint32_t)buffer[1]) << 16) | 
			(((uint32_t)buffer[2]) << 8) | 
			((uint32_t)buffer[0]));
	
realValueOfTemperature = * (float *) &tempTemp;
NRF_LOG_INFO("Temperature: " NRF_LOG_FLOAT_MARKER "Degree C. \r\n", NRF_LOG_FLOAT(realValueOfTemperature));


buffer[0] = 0x42;
buffer[1] = 0x43;
buffer[2] = 0x3A;
buffer[3] = 0x1B;
tempHumi = (uint32_t) ((((uint32_t)buffer[0]) << 24) | 
			(((uint32_t)buffer[1]) << 16) | 
			(((uint32_t)buffer[2]) << 8) | 
			((uint32_t)buffer[0]));
	
realValueOfHumidity = * (float *) &tempHumi;
NRF_LOG_INFO("Humidity: " NRF_LOG_FLOAT_MARKER "%%. \r\n", NRF_LOG_FLOAT(realValueOfHumidity));