SAM4L Datasheet, PDF (163/1185 Pages) ATMEL Corporation – ATSAM ARM-based Flash MCU

ATSAM4L4/L2
12.6.4.2
1MHz RC Oscillator
The 1MHz RC Oscillator which is used for switching regulator operation can also be internally
routed to be used as a logic clock. This oscillator is controlled by the RC1MCR register. Its
startup calibration value is read from flash fuses.
12.6.5 Bandgap
Rev: 1.1.0.7
The Bandgap provides a stable voltage reference used by the internally by the device. This ref-
erence is automatically turned on at startup. To save power consumption, the Bandgap features
a Low Power Bandgap voltage reference which may be automatically enabled in Wait or Ret
mode.
All modules using the Bandgap voltage reference, get their signal through a bandgap buffer.
These buffers are controlled automatically.
12.6.5.1
Temperature Sensor
The Bandgap voltage reference embeds a temperature sensor. To enable it, the BGCTRL.TSEN
bit should be set to one. The temperature sensor value can be converted thanks to the ADC.
12.6.6
Backup Registers (BR)
Rev: 1.0.0.1
Four 32-bit backup registers are available to store values when the device is in BACKUP Power
Save Mode. These registers will keep their content even when the VDDCORE supply and the
internal regulator supply voltage supplies are removed. The backup registers can be accessed
by reading from and writing to the BR0, BR1, BR2, and BR3 registers.
12.6.7 Interrupts
The SCIF has the following interrupt sources:
• AE - Access Error:
– A protected SCIF register was accessed without first being correctly unlocked.
• LPBGRDY- Access Error:
– A 0 to 1 transition on the PCLKSR.LPBGRDY bit is detected..
• VREGOK: Voltage Regulator OK:
– Set on 0 to 1 transition on the PCLKSR.VREGOK bit is detected.
• SSWRDY: Buck voltage regulator has stopped switching:
– Set on 0 to 1 transition on the PCLKSR.SSWRDY bit is detected.
• BOD18SYNRDY - BOD18 synchronization ready:
– Set on 0 to 1 transition on the PCLKSR.BOD18SYNRDY bit is detected.
• BOD33SYNRDY - BOD33 synchronization ready:
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