The configuration register of the voltage protection serves for defining the minimum value of the supply voltage, switching on/off the circuit for reseting the microcontroller if the supply voltage falls bellow the specified value, and for adjustment of the PWM output.The proper execution of programs requires a godd stability of the power supply. The family of microcontrollers dsPIC30F has the ability of defining a minimum power supply voltage ensuring proper functioning of the device. If the supply voltage falls below this limit, the internal circuit will reset the microcontroller, wait until the supply voltage returns above the limit, and after the specified power-up delay time activate the microcontroller starting the execution of the program for the beginning. The adjustment of the PWM output, more elaborated in Chapter 6 Output Compare Module, makes also the contents of this register. It is possible to select the states of PWM pins at a device reset (high impedance or output) and the active signal polarity for the PWM pins. The polarity for the high side and low side PWM pins may be selected independently.
Table 2-4. The voltage protection configuration register FBORPOR
(Table 2-4. continued
MCLREN – Pin function enable bit below the specified value 1 - Pin function enabled (default) 0 - Pin is disabled PWMPIN – The state of PWM at device reset 1 - PWM pin is in the state of high impedance at device reset 0 - PWM pin is configured as output at device reset HPOL – High side polarity bit 1 - High side output pin has active-high output polarity 0 - High side output pin has active-low output polarity LPOL - Low side polarity bit 1 - Low side output pin has active-high output polarity 0 - Low side output pin has active-low output polarity BOEN – Enable bit 1 - PBOR enabled 0 - PBOR disabled BORV <1:0> - Minimum supply voltage select bits 11 - 2.0V 10 - 2.7V 01 - 4.2V 00 - 4.5V FPWRT <1:0> - Power-on reset timer value selection bits 11 - 64ms 10 - 16ms 01 - 4ms 00 - 0ms