MSP430 datasheet(39/88 Pages) TI

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7.3.3.5 ADC Alarm Function

The AFEx8101 provide independent out-of-range detection for each of the ADC inputs. Figure 7-13 shows the

out-of-range detection block. When the measurement is out of range, the corresponding alarm bit is set to flag

the out-of-range condition.

AIN0_THRESHOLD [15:8]

AIN1_THRESHOLD [15:8]

TEMP_THRESHOLD [15:8]

Upper threshold

AIN0_THRESHOLD [7:0]

AIN1_THRESHOLD [7:0]

TEMP_THRESHOLD [7:0]

Lower threshold

–

ADC conversion value

–

ALARM_STATUS

ADC_AIN0_FLT,

ADC_AIN1_FLT,

ADC_TMP_FLT

Figure 7-13. ADC Out-of-Range Alarm

An alarm event is only registered when the monitored signal is out of range for N number of consecutive

conversions, where N is configured in the ADC_CFG.FLT_CNT false alarm register settings. If the monitored

signal returns to the normal range before N consecutive conversions, an alarm event is not issued.

If an ADC input signal is out of range and the alarm is enabled, then the corresponding alarm bit is set to

1. However, the alarm condition is cleared only when the conversion result returns to a value less than the

high-limit register setting and greater than the low-limit register setting by the number of codes specified by the

hysteresis setting (see Figure 7-14). The hysteresis is a programmable value between 0 LSB to 127 LSB in the

ADC_CFG.HYST register.

High Threshold

Low Threshold

Over High Alarm

Below Low Alarm

Hysteresis

Figure 7-14. ADC Alarm Hysteresis

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AFE78101, AFE88101

SLASF21 – DECEMBER 2022

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