static void ds18x20Select(ds18x20Dev *dev)
{
uint8_t i;
ds18x20SendByte(DS18X20_CMD_MATCH_ROM);
for (i = 0; i < 8; i++)
ds18x20SendByte(dev->id[i]);
return;
}
static void ds18x20ConvertTemp(void)
{
ds18x20SendByte(DS18X20_CMD_SKIP_ROM);
ds18x20SendByte(DS18X20_CMD_CONVERT);
#ifdef DS18X20_PARASITE_POWER
// Set active 1 on port for at least 750ms as parasitic power
PORT(ONE_WIRE) |= ONE_WIRE_LINE;
DDR(ONE_WIRE) |= ONE_WIRE_LINE;
#endif
return;
}
static void convertTemp(void)
{
ds18x20SendByte(DS18X20_CMD_SKIP_ROM);
ds18x20SendByte(DS18X20_CMD_CONVERT);
#ifdef DS18X20_PARASITE_POWER
/* Set active 1 on port for 750ms as parasitic power */
DS18X20_PORT |= DS18X20_WIRE;
DS18X20_DDR |= DS18X20_WIRE;
#endif
setTempTimer(TEMP_MEASURE_TIME);
return;
}
static void ds18x20GetAllTemps()
{
uint8_t i, j;
uint8_t crc;
static uint8_t arr[DS18X20_SCRATCH_LEN];
for (i = 0; i < devCount; i++) {
if (ds18x20IsOnBus()) {
ds18x20Select(&devs[i]);
ds18x20SendByte(DS18X20_CMD_READ_SCRATCH);
// Control scratchpad checksum
crc = 0;
for (j = 0; j < DS18X20_SCRATCH_LEN; j++) {
arr[j] = ds18x20GetByte();
crc = _crc_ibutton_update(crc, arr[j]);
}
if (crc == 0) {
// Save first 2 bytes (temperature) of scratchpad
for (j = 0; j < DS18X20_SCRATCH_TEMP_LEN; j++)
devs[i].sp[j] = arr[j];
}
}
}
return;
}
static uint8_t ds18x20SearchRom(uint8_t *bitPattern, uint8_t lastDeviation)
{
uint8_t currBit;
uint8_t newDeviation = 0;
uint8_t bitMask = 0x01;
uint8_t bitA;
uint8_t bitB;
// Send SEARCH ROM command on the bus
ds18x20SendByte(DS18X20_CMD_SEARCH_ROM);
// Walk through all 64 bits
for (currBit = 0; currBit < DS18X20_ID_LEN * 8; currBit++)
{
// Read bit from bus twice.
bitA = ds18x20GetBit();
bitB = ds18x20GetBit();
if (bitA && bitB) { // Both bits 1 = ERROR
return 0xFF;
} else if (!(bitA || bitB)) { // Both bits 0
if (currBit == lastDeviation) { // Select 1 if device has been selected
*bitPattern |= bitMask;
} else if (currBit > lastDeviation) { // Select 0 if no, and remember device
(*bitPattern) &= ~bitMask;
newDeviation = currBit;
} else if (!(*bitPattern & bitMask)) { // Otherwise just remember device
newDeviation = currBit;
}
} else { // Bits differ
if (bitA)
*bitPattern |= bitMask;
else
*bitPattern &= ~bitMask;
}
// Send the selected bit to the bus.
ds18x20SendBit(*bitPattern & bitMask);
// Adjust bitMask and bitPattern pointer.
bitMask <<= 1;
if (!bitMask)
{
bitMask = 0x01;
bitPattern++;
}
}
return newDeviation;
}
void ds18x20GetAllTemps()
{
uint8_t i, j;
uint8_t arr[9];
for (i = 0; i < devCount; i++) {
if (ds18x20IsOnBus()) {
ds18x20Select(&devs[i]);
ds18x20SendByte(DS18X20_CMD_READ_SCRATCH);
for (j = 0; j < 9; j++)
arr[j] = ds18x20GetByte();
if (!calcCRC8(arr, sizeof(arr))) {
for (j = 0; j < 9; j++)
devs[i].sp[j] = arr[j];
}
}
}
return;
}
