SAMA5D44_14 Datasheet, PDF (1524/1776 Pages) ATMEL Corporation – Atmel | SMART ARM-based Embedded MPU

48. Analog-to-Digital Converter (ADC)
48.1
Description
The ADC is based on a 10-bit Analog-to-Digital Converter (ADC) managed by an ADC Controller providing
enhanced resolution up to 12 bits. Refer to Figure 48-1. "Analog-to-Digital Converter Block Diagram with
Touchscreen Mode". It also integrates a 5-to-1 analog multiplexer, making possible the analog-to-digital
conversions of 5 analog lines.The conversions extend from 0V to the voltage carried on pin ADVREF.
The ADC digital controller embeds circuitry to reduce the resolution down to 8 bits. The 8-bit resolution mode
prevents using 16-bit Peripheral DMA transfer into memory when only 8-bit resolution is required by the
application. Note that using this low resolution mode does not increase the conversion rate.
Conversion results are reported in a common register for all channels, as well as in a channel-dedicated register.
The 11-bit and 12-bit resolution modes are obtained by averaging multiple samples to decrease quantization
noise. For 11-bit mode, 4 samples are used, which gives a real sample rate of 1/4 of the actual sample frequency.
For 12-bit mode, 16 samples are used, giving a real sample rate of 1/16 of the actual sample frequency. This
arrangement allows conversion speed to be traded for better accuracy.
Software trigger, external trigger on rising edge of the ADTRG pin or internal triggers from Timer Counter output(s)
are configurable.
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 PWM fault input. This input can be asserted by
means of comparison circuitry in order 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.
Finally, the user can configure ADC timings, such as startup time and tracking time.
This ADC Controller includes a Resistive Touchscreen Controller. It supports 4-wire and 5-wire technologies.
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SAMA5D4 Series [DATASHEET]
Atmel-11238A-ATARM-SAMA5D4-Datasheet_30-Sep-14