AN4300 datasheet(13/40 Pages) STMICROELECTRONICS

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AN4300

SPC56xBx features to cover lighting needs

2.3

ADC (Analog-to-Digital Converter)

The 2 ADC module convert analog signals into digital form; ADC_0 with a 10-bit resolution

and ADC_1 with a 12-bit resolution offering normal, injected and trigger-injected modes.

The ADC module can be configured to provide up to 62 single-ended input channels with no

additional external logic, exapandable to 90 channels using an external multiplexer, all

driven by the ADC module logic.

When using the SPC56EC74:

•

The ADC channels 0–15 correspond to ANP pins 0–15 with a resolution of 10-bit or 12-

bit (depending on the choice of ADC_0 (10-bit resolution) or ADC_1 (12-bit resolution);

in both cases the used pins are the same (precision channels)

•

The ADC_0 channels 32–60 (28 channels) correspond to ANS pins 0–27 (extended

channel, medium occurrence) while the ADC_1 channels 32-44 corresponf to ANS pins

0-12

•

The ADC channels 64–95 correspond to ANX pins 0–3 (external multiplexer driven by

MA0–2 ADC pins; external channel, medium accuracy)

For the family SPC56xB/Cxx, 6 + 3 analog watchdogs (6 on 10-bit ADC, 3 on 12-bit ADC)

are present on the ADC peripheral.

The analog watchdogs provide the capability to generate an interrupt for continuous

hardware monitoring to determine if the converted channel value lies within a given guarded

area defined by user-specified threshold values. If the converted value lies outside the

guarded area, an interrupt is generated. The analog watchdog interrupts are well suited for

light bulb diagnostic purposes.

With SPC56xB/Cxx devices, the diagnosis value can be collected in hardware mode, thus

reducing the load on the CPU for this task. Moreover, one time within an input signal period,

a load is placed on the CPU when these values collected in hardware mode are checked

and when they are compared to certain thresholds.

The analog watchdog feature can reduce this CPU load by triggering an interrupt only when

a fault occurs, instead of one time for the period, because the diagnosis check is performed

in automatic mode.

AN4300 Datasheet(PDF) 13 Page - STMicroelectronics