Configuration¶

Every field of ntc_config_t, its default and the setter that changes it at run time.

GetDefaultNtcConfig() returns the defaults below (the NTCG163JF103FT1S on channel 0 of a 3.3 V, 10 kΩ divider). The constructor that takes an NtcType starts from the same defaults and loads that type's R25 and B. Change any field before construction, or with SetConfiguration() afterwards.

Fields¶

Field	Default	Setter
`type`	`NtcG163Jft103Ft1S`	constructor
`resistance_at_25c` (Ω)	10000	`SetConfiguration()`
`beta_value` (K)	3435	`SetBetaValue()`
`reference_voltage` (V)	3.3	`SetReferenceVoltage()`
`series_resistance` (Ω)	10000	`SetVoltageDivider()`
`calibration_offset` (°C)	0	`SetCalibrationOffset()`, `Calibrate()`
`conversion_method`	`Auto`	`SetConversionMethod()`
`adc_channel`	0	`SetAdcChannel()`
`adc_resolution_bits`	12	not used in the conversion
`sample_count`	1	`SetSamplingParameters()`
`sample_delay_ms`	0	`SetSamplingParameters()`
`min_temperature` (°C)	−40	`SetConfiguration()`
`max_temperature` (°C)	125	`SetConfiguration()`
`enable_filtering`	`false`	`SetFiltering()`
`filter_alpha`	0.1	`SetFiltering()`

What each one means¶

resistance_at_25c, beta_value: The thermistor's R25 and B from its datasheet. B must be 1000 K to 5000 K. Use B25/85 for a range around 25 °C to 85 °C, B25/50 for a lower one (Conversion methods).
reference_voltage: The supply of the divider, at R_SERIES, in volts. Measure it on the board (Hardware).
series_resistance: The fixed resistor between the supply and the ADC node, in ohms.
conversion_method: Auto and Mathematical use the Beta equation. LookupTable uses the type's datasheet table from −40 °C to +150 °C and falls back to Beta outside it (Conversion methods).
adc_channel: The channel number passed to your port. SetAdcChannel() asks the port's IsChannelAvailable() first.
sample_count, sample_delay_ms: Reads averaged per conversion, and the wait between them through the port's optional DelayMs() (API guide).
min_temperature, max_temperature: A reading outside this window returns TemperatureOutOfRange. Set it to what is physically possible for your sensor, so a broken divider shows up as an error.
enable_filtering, filter_alpha: An exponential moving average, α from 0 to 1.

A different thermistor¶

ntc_config_t cfg = GetDefaultNtcConfig();
cfg.type = NtcType::Custom;
cfg.resistance_at_25c = 100000.0F;   // a 100 kOhm part
cfg.beta_value = 4250.0F;            // its B25/85 (or B25/50) from the datasheet
cfg.series_resistance = 100000.0F;   // match R25 for the best resolution around 25 C
cfg.reference_voltage = 3.3F;
cfg.adc_channel = 0;
cfg.min_temperature = -20.0F;        // readings outside this window return TemperatureOutOfRange
cfg.max_temperature = 100.0F;

Ntc ntc(cfg, &adc);
return ntc.Initialize();             // false: invalid config, ADC not up, or no such channel

type only selects the defaults and the lookup table; Custom has no table, so it always uses the Beta equation. If your datasheet gives a resistance table but no B, compute B from two of its points with NTC::CalculateBetaValue().

Next¶

API guide shows the setters in use; Hardware helps choose the divider values.