181 lines
3.8 KiB
C
181 lines
3.8 KiB
C
/**
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* @file aht20.c
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* @author Myth
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* @version 0.2
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* @date 2021.10.15
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* @brief AHT20 驱动
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*/
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#include "systick.h"
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#include "softi2c.h"
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#include "aht20.h"
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#define I2C_Start SoftI2C_Start(&aht20_i2c)
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#define I2C_Stop SoftI2C_Stop(&aht20_i2c)
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#define I2C_WriteByte(__byte__) SoftI2C_WriteByte(&aht20_i2c, __byte__)
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#define I2C_ReadByte SoftI2C_ReadByte(&aht20_i2c)
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#define I2C_Ack SoftI2C_Ack(&aht20_i2c)
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#define I2C_NAck SoftI2C_NAck(&aht20_i2c)
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#define I2C_WaitAck SoftI2C_WaitAck(&aht20_i2c)
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SoftI2C_TypeDef aht20_i2c;
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uint8_t AHT20_Read_Status(void);
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/**
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* @brief 初始化 AHT20
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*/
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void AHT20_Init(void)
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{
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aht20_i2c.SDA_GPIO = AHT20_GPIO;
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aht20_i2c.SDA_Pin = AHT20_SDA_PIN;
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aht20_i2c.SCL_GPIO = AHT20_GPIO;
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aht20_i2c.SCL_Pin = AHT20_SCL_PIN;
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aht20_i2c.Delay_Time = 5;
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SoftI2C_Init(&aht20_i2c);
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Delay_ms(500);
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if (AHT20_Read_Status() & 0x18 == 0x18)
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return;
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I2C_Start;
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I2C_WriteByte(0x70);
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I2C_WaitAck;
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I2C_WriteByte(0xa8);
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I2C_WaitAck;
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I2C_WriteByte(0x00);
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I2C_WaitAck;
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I2C_WriteByte(0x00);
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I2C_WaitAck;
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I2C_Stop;
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Delay_ms(10);
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I2C_Start;
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I2C_WriteByte(0x70);
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I2C_WaitAck;
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I2C_WriteByte(0xbe);
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I2C_WaitAck;
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I2C_WriteByte(0x08);
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I2C_WaitAck;
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I2C_WriteByte(0x00);
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I2C_WaitAck;
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I2C_Stop;
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Delay_ms(20);
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}
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/**
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* @brief 读取 AHT20 状态字
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* @retval 状态字
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*/
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uint8_t AHT20_Read_Status(void)
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{
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uint8_t data;
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I2C_Start;
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I2C_WriteByte(0x71);
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I2C_WaitAck;
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data = I2C_ReadByte;
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I2C_NAck;
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I2C_Stop;
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return data;
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}
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/**
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* @brief 向 AHT20 发送测量命令。需等待 80ms 后才能读取数据
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*/
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void AHT20_Start(void)
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{
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//发送 AC 指令请求数据
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I2C_Start;
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I2C_WriteByte(0x70);
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I2C_WaitAck;
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I2C_WriteByte(0xac);
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I2C_WaitAck;
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I2C_WriteByte(0x33);
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I2C_WaitAck;
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I2C_WriteByte(0x00);
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I2C_WaitAck;
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I2C_Stop;
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}
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/**
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* @brief 读取 AHT20 数据。在发送测量命令至少 80ms 后调用
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* @param humi: 浮点数指针，储存湿度
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* @param temp: 浮点数指针，储存温度
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* @retval 读取成功返回 1，读取失败返回 0
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*/
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uint8_t AHT20_Read(float *humi, float *temp)
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{
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uint8_t byte1 = 0;
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uint8_t byte2 = 0;
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uint8_t byte3 = 0;
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uint8_t byte4 = 0;
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uint8_t byte5 = 0;
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uint8_t byte6 = 0;
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uint32_t data32 = 0;
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uint16_t count = 0;
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while (((AHT20_Read_Status() & 0x80) == 0x80)) //等待状态字最高位变为 1，说明数据准备完成
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{
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Delay_ms(1);
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if (count++ >= 100)
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return 0;
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}
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I2C_Start;
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I2C_WriteByte(0x71);
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I2C_WaitAck;
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byte1 = I2C_ReadByte; //状态字
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I2C_Ack;
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byte2 = I2C_ReadByte; //湿度数据
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I2C_Ack;
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byte3 = I2C_ReadByte; //湿度数据
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I2C_Ack;
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byte4 = I2C_ReadByte; //湿度/温度数据
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I2C_Ack;
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byte5 = I2C_ReadByte; //温度数据
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I2C_Ack;
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byte6 = I2C_ReadByte; //温度数据
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I2C_NAck;
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I2C_Stop;
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data32 = (data32 | byte2) << 8;
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data32 = (data32 | byte3) << 8;
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data32 = (data32 | byte4);
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data32 = data32 >> 4;
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*humi = (float)data32 * 100.0 / 1024.0 / 1024.0; //湿度
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data32 = 0;
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data32 = (data32 | byte4) << 8;
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data32 = (data32 | byte5) << 8;
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data32 = (data32 | byte6);
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data32 = data32 & 0xfffff;
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*temp = ((float)data32 * 200 * 10 / 1024 / 1024 - 500) / 10.0; //温度
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return 1;
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}
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/**
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* @brief 发送测量命令，等待 80ms 并读取 AHT20 数据
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* @param humi: 浮点数指针，储存湿度
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* @param temp: 浮点数指针，储存温度
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* @retval 读取成功返回 1，读取失败返回 0
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*/
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uint8_t AHT20_StartAndRead(float *humi, float *temp)
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{
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AHT20_Start();
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Delay_ms(80); //延时 80ms，等待 AHT20 生成数据
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return AHT20_Read(humi, temp);
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}
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