temp.c: refactor temperature reads into functions.
Every type of temp sensor has its own special way to be read and the once-simple loop has grown complex. Restore some sanity by isolating the code for each sensor into its own inline function. In the process I noticed temp_flags is only ever set (never read) and is used only in MAX6675. I don't understand what it was used for, so for now, let's comment it out and revisit this later in this series.
This commit is contained in:
Phil Hord
Markus Hitter
parent
afb81f21be
commit
335437022c
154
temp.c
154
temp.c
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@ -79,7 +79,7 @@ static const temp_sensor_definition_t temp_sensors[NUM_TEMP_SENSORS] =
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/// this struct holds the runtime sensor data- read temperatures, targets, etc
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struct {
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temp_flags_enum temp_flags; ///< flags
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//temp_flags_enum temp_flags; ///< flags
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uint16_t last_read_temp; ///< last received reading
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uint16_t target_temp; ///< manipulate attached heater to attempt to achieve this value
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@ -283,6 +283,90 @@ static uint16_t temp_table_lookup(uint16_t temp, uint8_t sensor) {
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}
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#endif /* TEMP_THERMISTOR || TEMP_MCP3008 */
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#ifdef TEMP_MAX6675
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static uint16_t temp_read_max6675(temp_sensor_t i) {
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// Note: value reading in this section was rewritten without
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// testing when spi.c/.h was introduced. --Traumflug
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spi_select_max6675();
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// No delay required, see
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// https://github.com/Traumflug/Teacup_Firmware/issues/22
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// Read MSB.
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temp = spi_rw(0) << 8;
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// Read LSB.
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temp |= spi_rw(0);
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spi_deselect_max6675();
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// FIXME: No one ever reads temp_flags. It should be removed.
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//temp_sensors_runtime[i].temp_flags = 0;
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if ((temp & 0x8002) == 0) {
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// Got "device id".
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//temp_sensors_runtime[i].temp_flags |= PRESENT;
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if (temp & 4) {
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// Thermocouple open.
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//temp_sensors_runtime[i].temp_flags |= TCOPEN;
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}
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else {
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temp = temp >> 3;
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}
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}
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// MAX6675 can give a reading every 0.22s, so set this to about 250ms.
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temp_sensors_runtime[i].next_read_time = 25;
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return temp;
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}
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#endif /* TEMP_MAX6675 */
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#ifdef TEMP_THERMISTOR
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static uint16_t temp_read_thermistor(temp_sensor_t i) {
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temp_sensors_runtime[i].next_read_time = ANALOG_READ_INTERVAL;
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return temp_table_lookup(analog_read(i), i);
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}
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#endif /* TEMP_THERMISTOR */
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#ifdef TEMP_MCP3008
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static uint16_t temp_read_mcp3008(temp_sensor_t i) {
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// This is an SPI read so it is not as fast as on-chip ADC. A read
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// every 100ms should be sufficient.
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temp_sensors_runtime[i].next_read_time = 10;
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return temp_table_lookup(mcp3008_read(temp_sensors[i].temp_pin), i);
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}
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#endif /* TEMP_MCP3008 */
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#ifdef TEMP_AD595
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static uint16_t temp_read_ad595(temp_sensor_t i) {
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temp_sensors_runtime[i].next_read_time = ANALOG_READ_INTERVAL;
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// Convert >> 8 instead of >> 10 because internal temp is stored as
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// 14.2 fixed point.
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return (analog_read(i) * 500L) >> 8;
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}
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#endif /* TEMP_AD595 */
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#ifdef TEMP_INTERCOM
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static uint16_t temp_read_intercom(temp_sensor_t i) {
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temp_sensors_runtime[i].next_read_time = 25;
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return read_temperature(temp_sensors[i].temp_pin);
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}
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#endif /* TEMP_INTERCOM */
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#ifdef TEMP_DUMMY
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static uint16_t temp_read_dummy(temp_sensor_t i) {
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uint16_t temp = temp_sensors_runtime[i].last_read_temp;
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temp_sensors_runtime[i].next_read_time = 1;
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if (temp_sensors_runtime[i].target_temp > temp)
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temp++;
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else if (temp_sensors_runtime[i].target_temp < temp)
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temp--;
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return temp;
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}
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#endif /* TEMP_DUMMY */
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/// called every 10ms from clock.c - check all temp sensors that are ready for checking
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void temp_sensor_tick() {
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temp_sensor_t i = 0;
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@ -295,69 +379,25 @@ void temp_sensor_tick() {
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switch(temp_sensors[i].temp_type) {
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#ifdef TEMP_MAX6675
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case TT_MAX6675:
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// Note: value reading in this section was rewritten without
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// testing when spi.c/.h was introduced. --Traumflug
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spi_select_max6675();
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// No delay required, see
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// https://github.com/triffid/Teacup_Firmware/issues/22
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// read MSB
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temp = spi_rw(0) << 8;
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// read LSB
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temp |= spi_rw(0);
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spi_deselect_max6675();
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temp_sensors_runtime[i].temp_flags = 0;
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if ((temp & 0x8002) == 0) {
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// got "device id"
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temp_sensors_runtime[i].temp_flags |= PRESENT;
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if (temp & 4) {
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// thermocouple open
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temp_sensors_runtime[i].temp_flags |= TCOPEN;
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}
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else {
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temp = temp >> 3;
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}
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}
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// 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
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temp_sensors_runtime[i].next_read_time = 25;
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temp = temp_read_max6675(i);
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break;
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#endif /* TEMP_MAX6675 */
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#ifdef TEMP_THERMISTOR
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case TT_THERMISTOR:
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// Read current temperature.
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temp = temp_table_lookup(analog_read(i), i);
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temp_sensors_runtime[i].next_read_time = ANALOG_READ_INTERVAL;
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temp = temp_read_thermistor(i);
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break;
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#endif /* TEMP_THERMISTOR */
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#ifdef TEMP_MCP3008
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case TT_MCP3008:
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// Read current temperature.
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temp = temp_table_lookup(mcp3008_read(temp_sensors[i].temp_pin), i);
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// This is an SPI read so it is not as fast as on-chip ADC. A read
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// every 100ms should be sufficient.
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temp_sensors_runtime[i].next_read_time = 10;
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temp = temp_read_mcp3008(i);
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break;
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#endif /* TEMP_MCP3008 */
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#ifdef TEMP_AD595
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case TT_AD595:
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temp = analog_read(i);
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// convert
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// >>8 instead of >>10 because internal temp is stored as 14.2 fixed point
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temp = (temp * 500L) >> 8;
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temp_sensors_runtime[i].next_read_time = ANALOG_READ_INTERVAL;
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temp = temp_read_ad595(i);
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break;
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#endif /* TEMP_AD595 */
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@ -369,30 +409,20 @@ void temp_sensor_tick() {
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#ifdef TEMP_INTERCOM
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case TT_INTERCOM:
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temp = read_temperature(temp_sensors[i].temp_pin);
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temp_sensors_runtime[i].next_read_time = 25;
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temp = temp_read_intercom(i);
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break;
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#endif /* TEMP_INTERCOM */
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#ifdef TEMP_DUMMY
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case TT_DUMMY:
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temp = temp_sensors_runtime[i].last_read_temp;
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if (temp_sensors_runtime[i].target_temp > temp)
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temp++;
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else if (temp_sensors_runtime[i].target_temp < temp)
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temp--;
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temp_sensors_runtime[i].next_read_time = 1;
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temp = temp_read_dummy(i);
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break;
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#endif /* TEMP_DUMMY */
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default: /* prevent compiler warning */
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break;
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}
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/* Exponentially Weighted Moving Average alpha constant for smoothing
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noisy sensors. Instrument Engineer's Handbook, 4th ed, Vol 2 p126
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says values of 0.05 to 0.1 for TEMP_EWMA are typical. */
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