147 lines
3.4 KiB
C
147 lines
3.4 KiB
C
/*
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* sht30_driver.c
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*
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* Created on: 30. apr. 2025
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* Author: Christian L. V. Madsen (OZ1CM)
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*/
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#include "sht30_driver.h"
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#define REV16_A(X) (((X) << 8) | ((X)>>8))
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#define REV8_A(X) (((X) << 4) | ((X)>>4))
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static int isStructOk(SHT30_Struct_Type *inst){
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if(inst == NULL)return 0;
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if(inst->i2c_transfer_inst == NULL)return 0;
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if(inst->i2c_transfer_evt == NULL)return 0;
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return 1;
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}
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uint8_t crc8_i2c_u16(uint16_t input) {
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uint8_t crc = 0xFF;
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uint8_t poly = 0x31;
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// Process MSB first (big endian)
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for (int i = 1; i >= 0; i--) {
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uint8_t byte = (input >> (8 * i)) & 0xFF;
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crc ^= byte;
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for (uint8_t j = 0; j < 8; j++) {
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if (crc & 0x80)
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crc = (crc << 1) ^ poly;
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else
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crc <<= 1;
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}
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}
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return crc; // Final XOR is 0x00, so this is the final CRC
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}
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static int readRegister(SHT30_Struct_Type *inst, uint8_t *data_addr, uint8_t *data, uint32_t len){
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// Write what kind of addr we would like to read from:
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int ret = inst->i2c_transfer_evt(inst->i2c_transfer_inst,data_addr,2, SHT30_I2C_SET);
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// Read data:
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ret += inst->i2c_transfer_evt(inst->i2c_transfer_inst,data,len, SHT30_I2C_GET);
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return ret;
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}
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static int writeRegister(SHT30_Struct_Type *inst, uint16_t data_addr, uint8_t *data, uint32_t len){
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// Write what kind of addr we would like to read from:
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inst->i2c_transfer_evt(inst->i2c_transfer_inst,(uint8_t *)&data_addr,2, SHT30_I2C_SET);
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// Write data:
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inst->i2c_transfer_evt(inst->i2c_transfer_inst,data,len, SHT30_I2C_SET);
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return 0;
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}
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int sht30_writeCmd(SHT30_Struct_Type *inst, uint16_t command){
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if(!isStructOk(inst))return 1;
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int ret;
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uint8_t buffer[2] = {0};
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buffer[0] = (command >> 8) & 0xff;
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buffer[1] = (command & 0xff);
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ret = inst->i2c_transfer_evt(inst->i2c_transfer_inst,buffer,sizeof(buffer), SHT30_I2C_SET);
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return ret;
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}
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static int SHT30_resetConnection(SHT30_Struct_Type *inst){
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if(!isStructOk(inst))return 1;
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for(int i = 0; i< 3; i++){
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int ret = 0;
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ret = sht30_writeCmd(inst,0x30A2); // Soft reset device
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ret = sht30_writeCmd(inst,0x272A); // Measurement Command for Periodic Data Acquisition Mode
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if(ret == 0){
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return 0;
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}
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}
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return 1;
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}
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void SHT30_calcRawData(SHT30_Struct_Type *p){
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p->Message.RawTemp = REV16_A(p->Message.RawTemp);
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p->Message.RawHumidity = REV16_A(p->Message.RawHumidity);
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if(crc8_i2c_u16(p->Message.RawTemp) != p->Message.CRC_Temp) return;
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if(crc8_i2c_u16(p->Message.RawHumidity) != p->Message.CRC_Humidity) return;
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// Calc Temperature
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p->Temperature_mC = p->Message.RawTemp * 17500;
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p->Temperature_mC = p->Temperature_mC >> 16;
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p->Temperature_mC -= 4500;
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// Calc Humidity
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p->Humidity = p->Message.RawHumidity * 100;
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p->Humidity = p->Humidity >> 16;
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}
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int sht30_ReadData(SHT30_Struct_Type *inst){
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int ret;
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uint8_t reg[2] = {0xe0,0x00};
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ret = readRegister(inst, reg, (void*)&inst->Message, sizeof(SHT30_Message_Type));
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if(ret != 0){
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SHT30_resetConnection(inst);
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return 1;
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}else{
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SHT30_calcRawData(inst);
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return 0;
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}
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}
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int sht30_init(SHT30_Struct_Type *inst, void *i2c_transfer_inst, setGet_I2C_Event_fpt i2c_transfer_evt){
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if(inst == NULL)return -1;
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if(i2c_transfer_inst == NULL)return -1;
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if(i2c_transfer_evt == NULL)return -1;
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inst->i2c_transfer_inst = i2c_transfer_inst;
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inst->i2c_transfer_evt = i2c_transfer_evt;
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SHT30_resetConnection(inst);
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return 0;
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} |