Datasheet

Figure 33-2. ADC Prescaler
GCLK_ADC 9-BIT PRESCALER
CTRLB.PRESCALER[2:0]
DIV512
DIV256
DIV128
DIV64
DIV32
DIV16
DIV8
DIV4
CLK_ADC
The propagation delay of an ADC measurement depends on the selected mode and is given by:
• Single-shot mode:
PropagationDelay =
1 +
Resolution
2
+ DelayGain

CLK+  ADC
• Free-running mode:
PropagationDelay =
Resolution
2
+ DelayGain

CLK+  ADC
Table 33-1. Delay Gain
Delay Gain (in CLK_ADC Period)
INTPUTCTRL.GAIN[3:0] Free-running mode Single shot mode
Name Differential
Mode
Single-Ended
Mode
Differential
mode
Single-Ended
mode
1X 0x0 0 0 0 1
2X 0x1 0 1 0.5 1.5
4X 0x2 1 1 1 2
8X 0x3 1 2 1.5 2.5
16X 0x4 2 2 2 3
Reserved 0x5 ... 0xE Reserved Reserved Reserved Reserved
DIV2 0xF 0 1 0.5 1.5
33.6.4 ADC Resolution
The ADC supports 8-bit, 10-bit or 12-bit resolution. Resolution can be changed by writing the Resolution
bit group in the Control B register (CTRLB.RESSEL). By default, the ADC resolution is set to 12 bits.
SAM D21 Family
ADC – Analog-to-Digital Converter
© 2018 Microchip Technology Inc.
Datasheet Complete
DS40001882D-page 896