MAX32650 ADT7420 Temperature sensor demo

main.c

/******************************************************************************
 * Quick test of the ADT7420 temperature PMOD eval board
 ******************************************************************************/

/***** Includes *****/
#include <stdio.h>
#include <stdint.h>
#include <string.h>

#include "i2c.h"
#include "mxc_device.h"
#include "mxc_delay.h"

/***** Definitions *****/
#define I2C_PORT    MXC_I2C1 ///< I2C instance
#define I2C_FREQ    100000 ///< I2C clock frequency


#define TEMP_DEV_ADDR   0x48
#define TEMP_REG_MSB    0x00
#define TEMP_REG_LSB    0x01
#define TEMP_REG_CONFIG 0x03
// *****************************************************************************
void i2c_clear(){
    MXC_I2C_ClearRXFIFO(I2C_PORT);
    MXC_I2C_ClearTXFIFO(I2C_PORT);
}

int read_reg(uint8_t addr, uint8_t *recv_buffer, uint8_t len) {
    uint8_t write_data = addr;
    mxc_i2c_req_t reqMaster;

    i2c_clear();
    reqMaster.i2c = I2C_PORT;
    reqMaster.addr = TEMP_DEV_ADDR;
    reqMaster.tx_buf = &write_data;
    reqMaster.tx_len = 1;
    reqMaster.rx_buf = recv_buffer;
    reqMaster.rx_len = len;
    reqMaster.restart = 0;
    reqMaster.callback = NULL;
    int error = MXC_I2C_MasterTransaction(&reqMaster);
    if (error != E_NO_ERROR) printf("Couldn't read from the bus!\n");
    return error;
}

int write_byte_reg(uint8_t addr, uint8_t data){
    uint8_t write_data[2];
    mxc_i2c_req_t reqMaster;

    write_data[0] = addr;
    write_data[1] = data;

    i2c_clear();
    reqMaster.i2c = I2C_PORT;
    reqMaster.addr = TEMP_DEV_ADDR;
    reqMaster.tx_buf = write_data;
    reqMaster.tx_len = 2;
    reqMaster.rx_buf = NULL;
    reqMaster.rx_len = 0;
    reqMaster.restart = 0;
    reqMaster.callback = NULL;
    int error = MXC_I2C_MasterTransaction(&reqMaster);
    if (error != E_NO_ERROR) printf("Couldn't write to the bus!\n");
    return error;
}


void init_temp_sensor(){
    uint8_t rxbuff;
    
    // Set data format to 16 bits format
    printf("Configuring ADT7420 for 16 bit conversions\n");
    read_reg(TEMP_REG_CONFIG, &rxbuff, 1);
    printf("Config before: %02x\n", rxbuff);
    // Set 7th bit
    rxbuff |= 0b10000000;
    write_byte_reg(TEMP_REG_CONFIG, rxbuff);
    read_reg(TEMP_REG_CONFIG, &rxbuff, 1);
    printf("Config after : %02x\n", rxbuff);
}


uint16_t read_temperature_raw(){
    uint8_t tempbuffer[2];
    read_reg(TEMP_REG_MSB, tempbuffer, 2);
    return (tempbuffer[0]<<8) | (tempbuffer[1]&0xff);
}


float read_temperature(){
    // We assume that we successfully enabled 16-bit mode
    uint16_t tempRaw = read_temperature_raw();
    if (((tempRaw>>15) & 0x1) == 1){
        // Negative
        return (long)(tempRaw - 65536)/128.0;
    }
    return (long)tempRaw / 128.0;
}

int main(void) {
    int error = E_NO_ERROR;
    float temperature;

    error = MXC_I2C_Init(I2C_PORT, 1, 0);
    if (error != E_NO_ERROR) {
        printf("I2C master configure failed with error %i\n", error);
        return error;
    }

    MXC_I2C_SetFrequency(I2C_PORT, I2C_FREQ);
    init_temp_sensor();
    while (1) {
        temperature = read_temperature();
        printf("Current temperature is %0.2f C\n", (double)temperature);
        MXC_Delay(MXC_DELAY_SEC(1));
    }

    return E_NO_ERROR;
}