/*
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* sht30.c
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*
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* Created on: Aug 9, 2021
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* Author: Think
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*/
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#include <stdio.h>
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#include "stm32l4xx_hal.h"
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#include "sht30.h"
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//#define CONFIG_GPIO_I2C
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#ifdef CONFIG_GPIO_I2C
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#include "gpio_i2c_sht30.h"
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#else
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#include "i2c.h"
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#endif
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//#define CONFIG_SHT30_DEBUG
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#ifdef CONFIG_SHT30_DEBUG
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#define sht30_print(format,args...) printf(format, ##args)
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#else
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#define sht30_print(format,args...) do{} while(0)
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#endif
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static int sht30_send_cmd(SHT30_CMD cmd)
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{
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uint8_t buf[2];
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buf[0] = cmd >> 8;
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buf[1] = cmd;
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#ifdef CONFIG_GPIO_I2C
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return I2C_Master_Transmit(SHT30_ADDR_WR, (uint8_t*)buf, 2);
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#else
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return HAL_I2C_Master_Transmit(&hi2c2, SHT30_ADDR_WR, (uint8_t*)buf, 2, 0xFFFF);
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#endif
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}
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static void sht30_soft_reset(void)
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{
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sht30_send_cmd(SOFT_RESET_CMD);
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HAL_Delay(1);
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}
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static int sht30_single_shot_measurement(uint8_t *buf, uint8_t buf_size)
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{
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uint16_t cmd = HIGH_ENABLED_CMD; /* High with clock stretching */
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uint8_t rv;
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if( !buf || buf_size<SHT30_DATA_SIZE )
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{
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sht30_print("%s(): Invalid input arguments\n", __func__);
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return -1;
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}
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rv = sht30_send_cmd(cmd);
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if( rv )
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{
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sht30_print("ERROR: SHT30 send measurement command failure, rv=%d\n", rv);
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sht30_soft_reset();
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return -2;
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}
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#ifdef CONFIG_GPIO_I2C
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rv = I2C_Master_Receive(SHT30_ADDR_RD, buf, SHT30_DATA_SIZE);
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#else
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rv = HAL_I2C_Master_Receive(&hi2c2, SHT30_ADDR_RD, buf, SHT30_DATA_SIZE, 0xFFFF);
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#endif
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if(rv)
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{
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sht30_print("ERROR: SHT30 read measurement result failure, rv=%d\n", rv);
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return -3;
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}
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return 0;
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}
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static uint8_t sht30_crc8(const uint8_t *data, int len)
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{
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const uint8_t POLYNOMIAL = 0x31; /* SHT30 CRC8 Polynomial: 0x31=x8 + x5 + x4 + 1 */
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uint8_t crc = 0xFF; /* SHT30 CRC8 Initialization: 0xFF */
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int i, j;
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for (i=0; i<len; ++i)
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{
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crc ^= *data++;
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for (j=0; j<8; ++j)
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{
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crc = ( crc & 0x80 )? (crc << 1) ^ POLYNOMIAL: (crc << 1);
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}
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}
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return crc;
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}
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int SHT30_SampleData(float *temperature, float *humidity)
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{
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uint8_t buf[SHT30_DATA_SIZE];
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int rv;
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uint16_t temp;
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uint16_t humd;
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uint8_t crc;
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if(!temperature || !humidity)
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{
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sht30_print("%s(): Invalid input arguments\n", __func__);
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return -1;
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}
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sht30_print("SHT30 start single short measurement\n");
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rv = sht30_single_shot_measurement(buf, SHT30_DATA_SIZE);
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if( rv )
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{
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sht30_print("SHT30 Single Short measurement failure, rv=%d\n", rv);
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return -2;
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}
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#ifdef CONFIG_SHT30_DEBUG
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{
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int i;
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sht30_print("SHT30 get %d bytes sample data: \n", SHT30_DATA_SIZE);
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for(i=0; i<SHT30_DATA_SIZE; i++)
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{
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sht30_print("0x%02x ", buf[i]);
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}
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sht30_print("\n");
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}
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#endif
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/* byte[0-1] is temperature value, and byte[2] is temperature CRC */
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crc = sht30_crc8(buf, 2);
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sht30_print("SHT30 temperature Cal_CRC: [%02x] EXP_CRC: [%02x]\n", crc, buf[2]);
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if( crc != buf[2])
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{
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sht30_print("SHT30 measurement temperature got CRC error\n");
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return -3;
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}
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/* byte[3-4] is humidity value, and byte[5] is humidity CRC */
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crc = sht30_crc8(&buf[3], 2);
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sht30_print("SHT30 humidity Cal_CRC: [%02x] EXP_CRC: [%02x]\n", crc, buf[5]);
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if( crc != buf[5])
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{
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sht30_print("SHT30 measurement temperature got CRC error\n");
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return -4;
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}
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temp = (buf[0]<<8) | buf[1];
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humd = (buf[3]<<8) | buf[4];
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*temperature = -45 + 175*((float)temp/65535);
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*humidity = 100 * ((float)humd / 65535);
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return 0;
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}
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