5.7.1 Brown-out Detection/Reset (BOD/BOR)

AVR and PIC32CM MCUs provide Brown-out Detection (BOD) and Brown-out Reset (BOR) to monitor supply voltages and ensure reliable operation by resetting or interrupting the device if the voltage drops below a programmable threshold. BOD and BOR features help protect the device from erratic behavior due to insufficient supply voltage. Table 5-27 shows a comparison of features between AVR and PIC32CM.

Table 5-27. AVR® and PIC32CM BOD/BOR Features
Feature/AspectAVR® BODPIC32CM BOD/BOR (SUPC/SYSCTRL)
IntegrationStand-alone BOD

Varies per device family:

Integrated into either the Supply Controller (SUPC) or the System Controller (SYSCTRL)

Supply Domains MonitoredMain supply

Varies per device family:

Main (programmable)

Core (internal, non-configurable)

I/O, Analog, VREG

Early Warning/InterruptVoltage Level Monitor (VLM) provides early warning interrupt

Interrupts on threshold crossing

Wake from sleep

Threshold Configuration

Programmable (via fuses)

VLM as % above BOD

Programmable (from NVM/User Row/CFG) per domain
Operating Modes

Continuous

Sampled

Disabled

Continuous

Sampled (low power)

Reset ActionSystem reset on BOD event

System reset on BOR event

I/O reset on VDDIO drop

HysteresisN/AProgrammable hysteresis (from calibration)
Sleep Mode OperationSelectable modes for Active/SleepMonitoring in all modes, including Standby/Backup
CalibrationN/AThreshold/hysteresis values from Flash calibration
Status MonitoringVLM status, BOD statusStatus via SUPC/SYSCTRL registers, INTFLAG, etc.
Output PinsN/ASUPC (for supply status indication)