ErriezOregonTHN128.c

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/*
 * MIT License
 *
 * Copyright (c) 2020-2022 Erriez
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in all
 * copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 */
 
#include <string.h>
#include <stdio.h>
#include "ErriezOregonTHN128.h"
 
#define SET_ROL_ADDR(x)     (((x) & 0x07) << 0)
#define GET_ROL_ADDR(x)     (((x) & 0x07) << 0)
 
#define SET_CHANNEL(x)      ((((x) - 1) & 0x03) << 6)
#define GET_CHANNEL(x)      ((((x) >> 6) & 0x03) + 1)
 
#define SET_TEMP(x)         ((((((uint32_t)(x) / 100) % 10)) << 16) | \
                            ((((uint32_t)(x) / 10) % 10) << 12) | \
                            (((x) % 10) << 8))
#define GET_TEMP(x)         (((((x) >> 16) & 0x0f) * 100) + \
                            ((((x) >> 12) & 0x0f) * 10) + \
                            (((x) >> 8) & 0x0f))
 
#define SIGN_BIT            (1UL << 21)
 
#define LOW_BAT_BIT         (1UL << 23)
 
#define SET_CRC(x)          ((uint32_t)(x) << 24)
#define GET_CRC(x)          ((x) >> 24)
 
static uint8_t calcCrc(uint32_t rawData)
{
    uint16_t crc;
 
    /* Add Bytes 0, 1 and 2 */
    crc = ((rawData >> 16) & 0xff) + ((rawData >> 8) & 0xff) + ((rawData >> 0) & 0xff);
    /* Add most significant Byte of the CRC to the final CRC */
    crc = (crc >> 8) + (crc & 0xff);
 
    /* Return 8-bit CRC */
    return (uint8_t)crc;
}
 
bool OregonTHN128_CheckCRC(uint32_t rawData)
{
    return calcCrc(rawData) == GET_CRC(rawData);
}
 
/*------------------------------------------------------------------------------------------------*/
/*                                     Public functions                                           */
/*------------------------------------------------------------------------------------------------*/
void OregonTHN128_TempToString(char *temperatureStr, uint8_t temperatureStrLen, int16_t temperature)
{
    bool tempNegative = false;
    int tempAbs;
 
    /* Convert temperature without using float to string */
    tempAbs = temperature;
    if (temperature < 0) {
        tempNegative = true;
        tempAbs *= -1;
    }
 
    snprintf(temperatureStr, temperatureStrLen, "%s%d.%d",
             tempNegative ? "-" : "", (tempAbs / 10), tempAbs % 10);
}
 
uint32_t OregonTHN128_DataToRaw(OregonTHN128Data_t *data)
{
    uint32_t rawData;
 
    /* Rolling address 0..7 */
    rawData = SET_ROL_ADDR(data->rollingAddress);
 
    /* Set channel 1..3 */
    rawData |= SET_CHANNEL(data->channel);
 
    /* Set temperature -999..999 */
    if (data->temperature < 0) {
        rawData |= SIGN_BIT;
        rawData |= SET_TEMP(data->temperature * -1);
    } else {
        rawData |= SET_TEMP(data->temperature);
    }
 
    /* Low battery bit */
    if (data->lowBattery) {
        rawData |= LOW_BAT_BIT;
    }
 
    /* Calculate CRC */
    rawData |= SET_CRC(calcCrc(rawData));
 
    /* Return 32-bit raw data */
    return rawData;
}
 
bool OregonTHN128_RawToData(uint32_t rawData, OregonTHN128Data_t *data)
{
    memset(data, 0, sizeof(OregonTHN128Data_t));
 
    /* Set data structure */
    data->rawData = rawData;
    data->rollingAddress = GET_ROL_ADDR(rawData);
    data->channel = GET_CHANNEL(rawData);
    data->temperature = GET_TEMP(rawData);
    if (rawData & SIGN_BIT) {
        data->temperature *= -1;
    }
    data->lowBattery = (rawData & LOW_BAT_BIT) ? true : false;
 
    /* Return CRC success or failure */
    return calcCrc(rawData) == GET_CRC(rawData);
}