The purpose of the ADC is to measure
analog signals and convert them to a digital representation with minimal CPU
intervention providing for lower power and greater task integration.
The ADC supports fast 12-bit
analog-to-digital conversions. The ADC implements a 12-bit Successive Approximation
Register (SAR) core, sample/conversion mode control, and up to 6 independent
conversion-and-control buffers. This means the ADC allows up to 6 independent
analog-to-digital converter (ADC) samples to be converted and stored without any CPU
intervention.
ADC features include:
- 12-bit resolution conversion (based on SAR-12 core)
- Up to 12 (4 internal, 8 external) individually configurable analog input
channels
- Internal conversion channels for temperature sensing and supply
monitoring.
- External conversion channels accessible by GPIOs
- Full scale ADC operating voltage range (configurable 1.8V or 3.3V)
- Configurable ADC reference source: internal or external reference voltage
- Internal reference
- Voltage 1.4V (by on-chip Internal Reference Buffer)
- 1Msps sample rate
- External reference
- Voltage 1.8V (Shorted to VPP pin)
- 2Msps sample rate
- Configurable ADC clock source: SOC CLK or HFXT
- Sample-and-hold with programmable sampling periods controlled by software or
timers
- Different conversion modes: Single-channel, repeat-single-channel, sequence,
repeat-sequence, and software requested ad-hoc single conversion modes
- Window comparator with provision to configure low and high threshold values for
low-power monitoring of input signals from conversion-result registers
- Two sampling trigger sources: software trigger and event trigger
- Sixteen 12-bit conversion-result storage registers (MEMRES_0:15)
- Support for FIFO and non-FIFO modes for CPU and DMA
- Data compaction within FIFO for 32-bit reads
- Automatic and manual power down schemes
- Unsigned binary and two's complement data format
- Single and differential mode inputs
- 10-bit sample timer with two independent sample time compare registers
- Sample time compare value selection in each memory control register
- Different event sources with single event output