Data Sheet

203
Atmel | SMART SAM D21 [DATASHEET]
Atmel-42181G–SAM-D21_Datasheet–09/2015
16.8.16 Voltage References System (VREF) Control
Name: VREF
Offset: 0x40
Reset: 0x0XXX0000
Property: Write-Protected
z Bits 31:27 – Reserved
These bits are unused and reserved for future use. For compatibility with future devices, always write these bits to
zero when this register is written. These bits will always return zero when read.
z Bits 26:16 – CALIB[10:0]: Bandgap Voltage Generator Calibration
These bits are used to calibrate the output level of the bandgap voltage reference. These bits are loaded from
Flash Calibration Row at startup.
z Bits 15:3 – Reserved
These bits are unused and reserved for future use. For compatibility with future devices, always write these bits to
zero when this register is written. These bits will always return zero when read.
z Bit 2 – BGOUTEN: Bandgap Output Enable
0: The bandgap output is not available as an ADC input channel.
1: The bandgap output is routed to an ADC input channel.
z Bit 1 – TSEN: Temperature Sensor Enable
0: Temperature sensor is disabled.
1: Temperature sensor is enabled and routed to an ADC input channel.
Bit 3130292827262524
CALIB[10:8]
AccessRRRRRR/WR/WR/W
Reset00000XXX
Bit 2322212019181716
CALIB[7:0]
AccessR/WR/WR/WR/WR/WR/WR/WR/W
ResetXXXXXXXX
Bit 151413121110 9 8
AccessRRRRRRRR
Reset00000000
Bit 76543210
BGOUTEN TSEN
AccessRRRRRR/WR/WR
Reset00000000