lib_ds18b20.c

#include "../include/lib_ds18b20.h"
#include <stdio.h>
#include "ansi.h"

TaskHandle_t Ds18b20Handle;
extern _Noreturn void Task_Ds18b20(void *argument);

void Ds18b20_Init() {
    BaseType_t ret = xTaskCreate(
            Task_Ds18b20,
            "temperatureTask",
            256 * 4,
            NULL,
			osPriorityNormal,
            &Ds18b20Handle
            );

    if(ret != pdPASS){
        puts(ANSI_FG_RED "[Thermometers]" ANSI_FG_DEFAULT " failed!");
    }
}

uint8_t DS18B20_Start(OneWire_t *OneWire, uint8_t *ROM) {
    /* Check if device is DS18B20 */
    if (!DS18B20_Is(ROM)) {
        return 0;
    }

    /* Reset line */
    OneWire_Reset(OneWire);
    /* Select ROM number */
    OneWire_SelectWithPointer(OneWire, ROM);
    /* Start temperature conversion */
    OneWire_WriteByte(OneWire, DS18B20_CMD_CONVERTTEMP);

    return 1;
}

void DS18B20_StartAll(OneWire_t *OneWire) {
    /* Reset pulse */
    OneWire_Reset(OneWire);
    /* Skip rom */
    OneWire_WriteByte(OneWire, ONEWIRE_CMD_SKIPROM);
    /* Start conversion on all connected devices */
    OneWire_WriteByte(OneWire, DS18B20_CMD_CONVERTTEMP);
}

uint8_t DS18B20_Read(OneWire_t *OneWire, uint8_t *ROM, float *destination) {
    uint16_t temperature;
    uint8_t resolution;
    int8_t digit, minus = 0;
    float decimal;
    uint8_t i;
    uint8_t data[9];
    uint8_t crc;

    /* Check if device is DS18B20 */
    if (!DS18B20_Is(ROM)) {
        return 1;
    }

    /* Check if line is released, if it is, then conversion is complete */
    if (!OneWire_ReadBit(OneWire)) {
        /* Conversion is not finished yet */
        return 2;
    }

    /* Reset line */
    OneWire_Reset(OneWire);
    /* Select ROM number */
    OneWire_SelectWithPointer(OneWire, ROM);
    /* Read scratchpad command by onewire protocol */
    OneWire_WriteByte(OneWire, ONEWIRE_CMD_RSCRATCHPAD);

    /* Get data */
    for (i = 0; i < 9; i++) {
        /* Read byte by byte */
        data[i] = OneWire_ReadByte(OneWire);
    }

    /* Calculate CRC */
    crc = OneWire_CRC8(data, 8);

    /* Check if CRC is ok */
    if (crc != data[8])
        /* CRC invalid */
        return 3;


    /* First two bytes of scratchpad are temperature values */
    temperature = data[0] | (data[1] << 8);

    /* Reset line */
    OneWire_Reset(OneWire);

    /* Check if temperature is negative */
    if (temperature & 0x8000) {
        /* Two's complement, temperature is negative */
        temperature = ~temperature + 1;
        minus = 1;
    }


    /* Get sensor resolution */
    resolution = ((data[4] & 0x60) >> 5) + 9;


    /* Store temperature integer digits and decimal digits */
    digit = temperature >> 4;
    digit |= ((temperature >> 8) & 0x7) << 4;

    /* Store decimal digits */
    switch (resolution) {
        case 9:
            decimal = (temperature >> 3) & 0x01;
            decimal *= (float) DS18B20_DECIMAL_STEPS_9BIT;
            break;
        case 10:
            decimal = (temperature >> 2) & 0x03;
            decimal *= (float) DS18B20_DECIMAL_STEPS_10BIT;
            break;
        case 11:
            decimal = (temperature >> 1) & 0x07;
            decimal *= (float) DS18B20_DECIMAL_STEPS_11BIT;
            break;
        case 12:
            decimal = temperature & 0x0F;
            decimal *= (float) DS18B20_DECIMAL_STEPS_12BIT;
            break;
        default:
            decimal = 0xFF;
            digit = 0;
    }

    /* Check for negative part */
    decimal = digit + decimal;
    if (minus)
        decimal = 0 - decimal;


    /* Set to pointer */
    *destination = decimal;

    /* Return 1, temperature valid */
    return 0;
}

uint8_t DS18B20_GetResolution(OneWire_t *OneWire, uint8_t *ROM) {
    uint8_t conf;

    if (!DS18B20_Is(ROM))
        return 0;

    /* Reset line */
    OneWire_Reset(OneWire);
    /* Select ROM number */
    OneWire_SelectWithPointer(OneWire, ROM);
    /* Read scratchpad command by onewire protocol */
    OneWire_WriteByte(OneWire, ONEWIRE_CMD_RSCRATCHPAD);

    /* Ignore first 4 bytes */
    OneWire_ReadByte(OneWire);
    OneWire_ReadByte(OneWire);
    OneWire_ReadByte(OneWire);
    OneWire_ReadByte(OneWire);

    /* 5th byte of scratchpad is configuration register */
    conf = OneWire_ReadByte(OneWire);

    /* Return 9 - 12 value according to number of bits */
    return ((conf & 0x60) >> 5) + 9;
}

uint8_t DS18B20_SetResolution(OneWire_t *OneWire, uint8_t *ROM, DS18B20_Resolution_t resolution) {
    uint8_t th, tl, conf;
    if (!DS18B20_Is(ROM))
        return 0;


    /* Reset line */
    OneWire_Reset(OneWire);
    /* Select ROM number */
    OneWire_SelectWithPointer(OneWire, ROM);
    /* Read scratchpad command by onewire protocol */
    OneWire_WriteByte(OneWire, ONEWIRE_CMD_RSCRATCHPAD);

    /* Ignore first 2 bytes */
    OneWire_ReadByte(OneWire);
    OneWire_ReadByte(OneWire);

    th = OneWire_ReadByte(OneWire);
    tl = OneWire_ReadByte(OneWire);
    conf = OneWire_ReadByte(OneWire);

    if (resolution == DS18B20_Resolution_9bits) {
        conf &= ~(1 << DS18B20_RESOLUTION_R1);
        conf &= ~(1 << DS18B20_RESOLUTION_R0);
    } else if (resolution == DS18B20_Resolution_10bits) {
        conf &= ~(1 << DS18B20_RESOLUTION_R1);
        conf |= 1 << DS18B20_RESOLUTION_R0;
    } else if (resolution == DS18B20_Resolution_11bits) {
        conf |= 1 << DS18B20_RESOLUTION_R1;
        conf &= ~(1 << DS18B20_RESOLUTION_R0);
    } else if (resolution == DS18B20_Resolution_12bits) {
        conf |= 1 << DS18B20_RESOLUTION_R1;
        conf |= 1 << DS18B20_RESOLUTION_R0;
    }

    /* Reset line */
    OneWire_Reset(OneWire);
    /* Select ROM number */
    OneWire_SelectWithPointer(OneWire, ROM);
    /* Write scratchpad command by onewire protocol, only th, tl and conf register can be written */
    OneWire_WriteByte(OneWire, ONEWIRE_CMD_WSCRATCHPAD);

    /* Write bytes */
    OneWire_WriteByte(OneWire, th);
    OneWire_WriteByte(OneWire, tl);
    OneWire_WriteByte(OneWire, conf);

    /* Reset line */
    OneWire_Reset(OneWire);
    /* Select ROM number */
    OneWire_SelectWithPointer(OneWire, ROM);
    /* Copy scratchpad to EEPROM of DS18B20 */
    OneWire_WriteByte(OneWire, ONEWIRE_CMD_CPYSCRATCHPAD);

    return 1;
}

uint8_t DS18B20_Is(uint8_t *ROM) {
    /* Checks if first byte is equal to DS18B20's family code */
    if (*ROM == DS18B20_FAMILY_CODE)
        return 1;

    return 0;
}

uint8_t DS18B20_SetAlarmLowTemperature(OneWire_t *OneWire, uint8_t *ROM, int8_t temp) {
    uint8_t tl, th, conf;
    if (!DS18B20_Is(ROM))
        return 0;

    if (temp > 125)
        temp = 125;

    if (temp < -55)
        temp = -55;

    /* Reset line */
    OneWire_Reset(OneWire);
    /* Select ROM number */
    OneWire_SelectWithPointer(OneWire, ROM);
    /* Read scratchpad command by onewire protocol */
    OneWire_WriteByte(OneWire, ONEWIRE_CMD_RSCRATCHPAD);

    /* Ignore first 2 bytes */
    OneWire_ReadByte(OneWire);
    OneWire_ReadByte(OneWire);

    th = OneWire_ReadByte(OneWire);
    tl = OneWire_ReadByte(OneWire);
    conf = OneWire_ReadByte(OneWire);

    tl = (uint8_t) temp;

    /* Reset line */
    OneWire_Reset(OneWire);
    /* Select ROM number */
    OneWire_SelectWithPointer(OneWire, ROM);
    /* Write scratchpad command by onewire protocol, only th, tl and conf register can be written */
    OneWire_WriteByte(OneWire, ONEWIRE_CMD_WSCRATCHPAD);

    /* Write bytes */
    OneWire_WriteByte(OneWire, th);
    OneWire_WriteByte(OneWire, tl);
    OneWire_WriteByte(OneWire, conf);

    /* Reset line */
    OneWire_Reset(OneWire);
    /* Select ROM number */
    OneWire_SelectWithPointer(OneWire, ROM);
    /* Copy scratchpad to EEPROM of DS18B20 */
    OneWire_WriteByte(OneWire, ONEWIRE_CMD_CPYSCRATCHPAD);

    return 1;
}

uint8_t DS18B20_SetAlarmHighTemperature(OneWire_t *OneWire, uint8_t *ROM, int8_t temp) {
    uint8_t tl, th, conf;
    if (!DS18B20_Is(ROM))
        return 0;

    if (temp > 125)
        temp = 125;

    if (temp < -55)
        temp = -55;

    /* Reset line */
    OneWire_Reset(OneWire);
    /* Select ROM number */
    OneWire_SelectWithPointer(OneWire, ROM);
    /* Read scratchpad command by onewire protocol */
    OneWire_WriteByte(OneWire, ONEWIRE_CMD_RSCRATCHPAD);

    /* Ignore first 2 bytes */
    OneWire_ReadByte(OneWire);
    OneWire_ReadByte(OneWire);

    th = OneWire_ReadByte(OneWire);
    tl = OneWire_ReadByte(OneWire);
    conf = OneWire_ReadByte(OneWire);

    th = (uint8_t) temp;

    /* Reset line */
    OneWire_Reset(OneWire);
    /* Select ROM number */
    OneWire_SelectWithPointer(OneWire, ROM);
    /* Write scratchpad command by onewire protocol, only th, tl and conf register can be written */
    OneWire_WriteByte(OneWire, ONEWIRE_CMD_WSCRATCHPAD);

    /* Write bytes */
    OneWire_WriteByte(OneWire, th);
    OneWire_WriteByte(OneWire, tl);
    OneWire_WriteByte(OneWire, conf);

    /* Reset line */
    OneWire_Reset(OneWire);
    /* Select ROM number */
    OneWire_SelectWithPointer(OneWire, ROM);
    /* Copy scratchpad to EEPROM of DS18B20 */
    OneWire_WriteByte(OneWire, ONEWIRE_CMD_CPYSCRATCHPAD);

    return 1;
}

uint8_t DS18B20_DisableAlarmTemperature(OneWire_t *OneWire, uint8_t *ROM) {
    uint8_t tl, th, conf;
    if (!DS18B20_Is(ROM))
        return 0;

    /* Reset line */
    OneWire_Reset(OneWire);
    /* Select ROM number */
    OneWire_SelectWithPointer(OneWire, ROM);
    /* Read scratchpad command by onewire protocol */
    OneWire_WriteByte(OneWire, ONEWIRE_CMD_RSCRATCHPAD);

    /* Ignore first 2 bytes */
    OneWire_ReadByte(OneWire);
    OneWire_ReadByte(OneWire);

    th = OneWire_ReadByte(OneWire);
    tl = OneWire_ReadByte(OneWire);
    conf = OneWire_ReadByte(OneWire);

    th = 125;
    tl = (uint8_t) -55;

    /* Reset line */
    OneWire_Reset(OneWire);
    /* Select ROM number */
    OneWire_SelectWithPointer(OneWire, ROM);
    /* Write scratchpad command by onewire protocol, only th, tl and conf register can be written */
    OneWire_WriteByte(OneWire, ONEWIRE_CMD_WSCRATCHPAD);

    /* Write bytes */
    OneWire_WriteByte(OneWire, th);
    OneWire_WriteByte(OneWire, tl);
    OneWire_WriteByte(OneWire, conf);

    /* Reset line */
    OneWire_Reset(OneWire);
    /* Select ROM number */
    OneWire_SelectWithPointer(OneWire, ROM);
    /* Copy scratchpad to EEPROM of DS18B20 */
    OneWire_WriteByte(OneWire, ONEWIRE_CMD_CPYSCRATCHPAD);

    return 1;
}

uint8_t DS18B20_AlarmSearch(OneWire_t *OneWire) {
    /* Start alarm search */
    return OneWire_Search(OneWire, DS18B20_CMD_ALARMSEARCH);
}

uint8_t DS18B20_AllDone(OneWire_t *OneWire) {
    /* If read bit is low, then device is not finished yet with calculation temperature */
    return OneWire_ReadBit(OneWire);
}