4.6.1 Target Regulator

The target voltage regulator is a MIC5353 variable output LDO. The on-board debugger can adjust the voltage output supplied to the board target section by manipulating the MIC5353’s feedback voltage. The hardware implementation is limited to an approximate voltage range from 1.7V to 5.1V. Additional output voltage limits are configured in the debugger firmware to ensure that the output voltage never exceeds the hardware limits of the PIC32CM3204GV00064 microcontroller. The voltage limits configured in the on-board debugger on PIC32CM GV-Value Line Curiosity Nano+ Touch board are 1.8 – 5.5V.

Info: The factory default target voltage is 5.0V. Any change to the target voltage is persistent, even after a power toggle. The resolution is less than 5 mV but may be limited to 10 mV by the adjustment program.
Info: The voltage settings setup in MPLAB X IDE is not applied immediately to the board. Like clicking the Refresh Debug Tool Status button in the project dashboard tab or programming or reading the program memory, the new voltage setting is applied to the board when accessing the debugger.
Figure 4-5. Target Regulator Safe Operation Area

The voltage output of the target regulator is continuously monitored (measured) by the on-board debugger. An error condition will be flagged and the target voltage regulator will be switched off, detecting and handling any short-circuit conditions if it is more than 100 mV over/under the set device voltage. It will detect and handle if an external voltage, which causes VCC_TARGET to move outside the voltage setting monitoring window of ±100 mV, is suddenly applied to the VTG pin without setting the VOFF pin low.

Info: The on-board debugger has a monitoring window of VCC_TARGET±100 mV, and the status LED will blink rapidly if the external voltage is under this limit. The on-board debugger status LED will continue to shine if the external voltage surpasses this limit. When removing the external voltage, the status LED will start blinking rapidly until the on-board debugger detects the new situation and turns the target voltage regulator back on.