5.2.1 Description

The ADC is based on a 12-bit Analog-to-Digital Converter (ADC) managed by an ADC Controller providing enhanced resolution up to 16 bits. The conversions extend from the voltage carried on pin GNDIN33 to the voltage carried on pin ADVREFP.

Conversion results are reported in a common register for all channels, as well as in a channel-dedicated register.

The 13-bit, 14-bit, 15-bit and 16-bit resolution modes are obtained by averaging multiple samples to decrease quantization noise. For the 13-bit mode, 4 samples are used, which gives a real sample rate of 1/4 of the actual sample frequency. For the 14-bit mode, 16 samples are used, giving a real sample rate of 1/16 of the actual sample frequency. For the 15-bit and 16-bit modes, respectively 64 and 256 samples are used, giving a real sample rate of respectively 1/64 and 1/256 of the actual sample frequency. This arrangement allows conversion speed to be traded off against for better accuracy.

The last channel is internally connected to the temperature sensor output voltage (VTEMP) or to the reference voltage (VBG). The selection is controlled in the analog control register (ADC_ACR).

The software trigger, external trigger on rising edge of the ADTRG pin or internal triggers from Timer Counter output(s) can be selected for triggering a conversion.

The comparison circuitry allows automatic detection of values below a threshold, higher than a threshold, in a given range or outside the range, thresholds and ranges being fully configurable.

The ADC Controller internal fault output is directly connected to the PWM fault input. This input can be asserted by means of a comparison circuitry to immediately put the PWM output in a safe state (pure combinational path).

The ADC also integrates a Sleep mode and a conversion sequencer and connects with a DMA channel. These features reduce both power consumption and processor intervention.

This ADC has a selectable single-ended or fully differential input.