SAM L10/L11 Digital-to-Analog Converter (DAC)
Overview
The Digital-to-Analog Converter (DAC) converts a digital value to a voltage. The DAC has one channel with a 10-bit resolution and it is capable of converting up to 350,000 samples per second (350 ksps).
Features
- DAC with 10-bit resolution
- Up to 350 ksps conversion rate
- Hardware support for 14-bit using dithering
- Multiple trigger sources
- High-drive capabilities
- Output can be used as input to the Analog Comparator (AC), Analog-to-Digital Converter (ADC), and Operational Amplifier Controller (OPAMP)
- Direct Memory Access (DMA) support
Block Diagram
Principle of Operation
Using the DAC Controller’s I/O lines requires the I/O pins to be configured using the IO Pin Controller (PORT).
The DAC has one output pin (VOUT) and one analog input pin (VREFA) that must be configured first. When internal input is used, it must be enabled before the DAC Controller is enabled.
The DAC bus clock (CLK_DAC_APB) can be enabled and disabled by the Main Clock module, and the default state of CLK_DAC_APB can be found in the Peripheral Clock Masking section. A generic clock (GCLK_DAC) is required to clock the DAC Controller. This clock must be configured and enabled in the Generic Clock Controller before using the DAC Controller. Refer to GCLK – Generic Clock Controller for details. This generic clock is asynchronous to the bus clock (CLK_DAC_APB). Due to this asynchronicity, writes to certain registers will require synchronization between the clock domains.
The DMA request line is connected to the DMA Controller (DMAC). Using the DAC Controller, DMA requests require to configure the DMAC first. The interrupt request line is connected to the interrupt controller. Using the DAC Controller interrupt(s) requires the interrupt controller to be configured first.
The DAC converts the digital value located in the data register (DATA) into an analog voltage on the DAC output (VOUT). A conversion is started when new data is written to the data register. The resulting voltage is available on the DAC output after the conversion time. A conversion can also be started by inputting events from the Event System.
