void temp_sensor_tick() {
temp_sensor_t i = 0;
for (; i < NUM_TEMP_SENSORS; i++) {
if (temp_sensors_runtime[i].next_read_time) {
temp_sensors_runtime[i].next_read_time--;
}
else {
uint16_t temp = 0;
//time to deal with this temp sensor
switch(temp_sensors[i].temp_type) {
#ifdef TEMP_MAX6675
case TT_MAX6675:
#ifdef PRR
PRR &= ~MASK(PRSPI);
#elif defined PRR0
PRR0 &= ~MASK(PRSPI);
#endif
SPCR = MASK(MSTR) | MASK(SPE) | MASK(SPR0);
// enable TT_MAX6675
WRITE(SS, 0);
// ensure 100ns delay - a bit extra is fine
delay(1);
// read MSB
SPDR = 0;
for (;(SPSR & MASK(SPIF)) == 0;);
temp = SPDR;
temp <<= 8;
// read LSB
SPDR = 0;
for (;(SPSR & MASK(SPIF)) == 0;);
temp |= SPDR;
// disable TT_MAX6675
WRITE(SS, 1);
temp_sensors_runtime[i].temp_flags = 0;
if ((temp & 0x8002) == 0) {
// got "device id"
temp_sensors_runtime[i].temp_flags |= PRESENT;
if (temp & 4) {
// thermocouple open
temp_sensors_runtime[i].temp_flags |= TCOPEN;
}
else {
temp = temp >> 3;
}
}
// this number depends on how frequently temp_sensor_tick is called. the MAX6675 can give a reading every 0.22s, so set this to about 250ms
temp_sensors_runtime[i].next_read_time = 25;
break;
#endif /* TEMP_MAX6675 */
#ifdef TEMP_THERMISTOR
case TT_THERMISTOR:
do {
uint8_t j;
//Read current temperature
temp = analog_read(temp_sensors[i].temp_pin);
//Calculate real temperature based on lookup table
for (j = 1; j < NUMTEMPS; j++) {
if (pgm_read_word(&(temptable[j][0])) > temp) {
// Thermistor table is already in 14.2 fixed point
if (debug_flags & DEBUG_PID)
sersendf_P(PSTR("pin:%d Raw ADC:%d table entry: %d"),temp_sensors[i].temp_pin,temp,j);
// Linear interpolating temperature value
// y = ((x - x₀)y₁ + (x₁-x)y₀ ) / (x₁ - x₀)
// y = temp
// x = ADC reading
// x₀= temptable[j-1][0]
// x₁= temptable[j][0]
// y₀= temptable[j-1][1]
// y₁= temptable[j][1]
// y =
// Wikipedia's example linear interpolation formula.
temp = (
// ((x - x₀)y₁
((uint32_t)temp - pgm_read_word(&(temptable[j-1][0]))) * pgm_read_word(&(temptable[j][1]))
// +
+
// (x₁-x)
(pgm_read_word(&(temptable[j][0])) - (uint32_t)temp)
// y₀ )
* pgm_read_word(&(temptable[j-1][1])))
// /
/
// (x₁ - x₀)
(pgm_read_word(&(temptable[j][0])) - pgm_read_word(&(temptable[j-1][0])));
if (debug_flags & DEBUG_PID)
sersendf_P(PSTR(" temp:%d.%d"),temp/4,(temp%4)*25);
break;
}
}
if (debug_flags & DEBUG_PID)
sersendf_P(PSTR(" Sensor:%d\n"),i);
//Clamp for overflows
if (j == NUMTEMPS)
temp = temptable[NUMTEMPS-1][1];
temp_sensors_runtime[i].next_read_time = 0;
} while (0);
break;
#endif /* TEMP_THERMISTOR */
#ifdef TEMP_AD595
case TT_AD595:
temp = analog_read(temp_pin);
// convert
// >>8 instead of >>10 because internal temp is stored as 14.2 fixed point
temp = (temp * 500L) >> 8;
temp_sensors_runtime[i].next_read_time = 0;
break;
#endif /* TEMP_AD595 */
#ifdef TEMP_PT100
case TT_PT100:
#warning TODO: PT100 code
break
#endif /* TEMP_PT100 */
#ifdef TEMP_INTERCOM
case TT_INTERCOM:
temp = get_read_cmd() << 2;
start_send();
temp_sensors_runtime[i].next_read_time = 0;
break;
#endif /* TEMP_INTERCOM */
#ifdef TEMP_DUMMY
case TT_DUMMY:
temp = temp_sensors_runtime[i].last_read_temp;
if (temp_sensors_runtime[i].target_temp > temp)
temp++;
else if (temp_sensors_runtime[i].target_temp < temp)
temp--;
temp_sensors_runtime[i].next_read_time = 0;
break;
#endif /* TEMP_DUMMY */
}
temp_sensors_runtime[i].last_read_temp = temp;
if (labs(temp - temp_sensors_runtime[i].target_temp) < TEMP_HYSTERESIS) {
if (temp_sensors_runtime[i].temp_residency < TEMP_RESIDENCY_TIME)
temp_sensors_runtime[i].temp_residency++;
}
else {
temp_sensors_runtime[i].temp_residency = 0;
}
if (temp_sensors[i].heater_index < NUM_HEATERS) {
heater_tick(temp_sensors[i].heater_index, i, temp_sensors_runtime[i].last_read_temp, temp_sensors_runtime[i].target_temp);
}
}
}
void temp_sensor_tick() {
temp_sensor_t i = 0;
for (; i < NUM_TEMP_SENSORS; i++) {
if (temp_sensors_runtime[i].next_read_time) {
temp_sensors_runtime[i].next_read_time--;
}
else {
uint16_t temp = 0;
//time to deal with this temp sensor
switch(temp_sensors[i].temp_type) {
#ifdef TEMP_MAX6675
case TT_MAX6675:
#ifdef PRR
PRR &= ~MASK(PRSPI);
#elif defined PRR0
PRR0 &= ~MASK(PRSPI);
#endif
SPCR = MASK(MSTR) | MASK(SPE) | MASK(SPR0);
// enable TT_MAX6675
WRITE(SS, 0);
// ensure 100ns delay - a bit extra is fine
delay(1);
// read MSB
SPDR = 0;
for (;(SPSR & MASK(SPIF)) == 0;);
temp = SPDR;
temp <<= 8;
// read LSB
SPDR = 0;
for (;(SPSR & MASK(SPIF)) == 0;);
temp |= SPDR;
// disable TT_MAX6675
WRITE(SS, 1);
temp_sensors_runtime[i].temp_flags = 0;
if ((temp & 0x8002) == 0) {
// got "device id"
temp_sensors_runtime[i].temp_flags |= PRESENT;
if (temp & 4) {
// thermocouple open
temp_sensors_runtime[i].temp_flags |= TCOPEN;
}
else {
temp = temp >> 3;
}
}
// this number depends on how frequently temp_sensor_tick is called. the MAX6675 can give a reading every 0.22s, so set this to about 250ms
temp_sensors_runtime[i].next_read_time = 25;
break;
#endif /* TEMP_MAX6675 */
#ifdef TEMP_THERMISTOR
case TT_THERMISTOR:
do {
uint8_t j;
//Read current temperature
temp = analog_read(temp_sensors[i].temp_pin);
//Calculate real temperature based on lookup table
for (j = 1; j < NUMTEMPS; j++) {
if (pgm_read_word(&(temptable[j][0])) > temp) {
// multiply by 4 because internal temp is stored as 14.2 fixed point
temp = pgm_read_word(&(temptable[j][1])) * 4 + (temp - pgm_read_word(&(temptable[j-1][0]))) * 4 * (pgm_read_word(&(temptable[j][1])) - pgm_read_word(&(temptable[j-1][1]))) / (pgm_read_word(&(temptable[j][0])) - pgm_read_word(&(temptable[j-1][0])));
break;
}
}
//Clamp for overflows
if (j == NUMTEMPS)
temp = temptable[NUMTEMPS-1][1] * 4;
temp_sensors_runtime[i].next_read_time = 0;
} while (0);
break;
#endif /* TEMP_THERMISTOR */
#ifdef TEMP_AD595
case TT_AD595:
temp = analog_read(temp_pin);
// convert
// >>8 instead of >>10 because internal temp is stored as 14.2 fixed point
temp = (temp * 500L) >> 8;
temp_sensors_runtime[i].next_read_time = 0;
break;
#endif /* TEMP_AD595 */
#ifdef TEMP_PT100
case TT_PT100:
#warning TODO: PT100 code
break
#endif /* TEMP_PT100 */
#ifdef TEMP_INTERCOM
case TT_INTERCOM:
temp = get_read_cmd() << 2;
start_send();
temp_sensors_runtime[i].next_read_time = 0;
break;
#endif /* TEMP_INTERCOM */
#ifdef TEMP_DUMMY
case TT_DUMMY:
temp = temp_sensors_runtime[i].last_read_temp;
if (temp_sensors_runtime[i].target_temp > temp)
temp++;
else if (temp_sensors_runtime[i].target_temp < temp)
temp--;
temp_sensors_runtime[i].next_read_time = 0;
break;
#endif /* TEMP_DUMMY */
}
temp_sensors_runtime[i].last_read_temp = temp;
if (labs(temp - temp_sensors_runtime[i].target_temp) < TEMP_HYSTERESIS) {
if (temp_sensors_runtime[i].temp_residency < TEMP_RESIDENCY_TIME)
temp_sensors_runtime[i].temp_residency++;
}
else {
temp_sensors_runtime[i].temp_residency = 0;
}
if (temp_sensors[i].heater_index < NUM_HEATERS) {
heater_tick(temp_sensors[i].heater_index, i, temp_sensors_runtime[i].last_read_temp, temp_sensors_runtime[i].target_temp);
}
}
}
