Unlock MCU PIC18F8720 Program

We can Unlock MCU PIC18F8720 Program, please view the MCU PIC18F8720 features for your reference:

The sequence of events that takes place when switching from the Timer1 oscillator to the main oscillator will depend on the mode of the main oscillator. In addition to eight clock cycles of the main oscillator, additional delays may take place when Unlock MCU.

If the main oscillator is configured for an external crystal (HS, XT, LP), then the transition will take place after an oscillator start-up time (TOST) has occurred. A timing diagram, indicating the transition from the Timer1 oscillator to the main oscillator for HS, XT and LP modes, is shown in Figure 2-9 if Unlock MCU

If the main oscillator is configured for HS-PLL mode, an oscillator start-up time (TOST), plus an additional PLL time-out (TPLL), will occur. The PLL time-out is typically 2 ms and allows the PLL to lock to the main oscillator frequency. A timing diagram, indicating the transition from the Timer1 oscillator to the main oscillator for HS-PLL mode, is shown in Figure 2-10 before Unlock MCU

If the main oscillator is configured in the RC, RCIO, EC or ECIO modes, there is no oscillator start-up time-out. Operation will resume after eight cycles of the main oscillator have been counted. A timing diagram, indicating the transition from the Timer1 oscillator to the main oscillator for RC, RCIO, EC and ECIO modes, is shown in Figure 2-11 after Unlock MCU

When the device executes a SLEEP instruction, the on-chip clocks and oscillator are turned off and the device is held at the beginning of an instruction cycle (Q1 state). With the oscillator off, the OSC1 and OSC2 signals will stop oscillating. Since all the transistor switching currents have been removed, Sleep mode achieves the lowest current consumption of the device (only leakage currents). Enabling any on-chip feature that will operate during Sleep will increase the current consumed during Sleep if Unlock MCU.

The user can wake from Sleep through external Reset, Watchdog Timer Reset or through an interrupt. Power up delays are controlled by two timers so that no external Reset circuitry is required for most applications. The delays ensure that the device is kept in Reset until the device power supply and clock are stable. For additional information on Reset operation, see Section 3.0 “Reset” when Unlock MCU.

The first timer is the Power-up Timer (PWRT), which optionally provides a fixed delay of 72 ms (nominal) on power-up only (POR and BOR). The second timer is the Oscillator Start-up Timer (OST), intended to keep the chip in Reset until the crystal oscillator is stable before Unlock MCU.

With the PLL enabled (HS/PLL Oscillator mode), the time-out sequence following a Power-on Reset is different from other oscillator modes. The time-out sequence is as follows: First, the PWRT time-out is invoked after a POR time delay has expired. Then, the Oscillator Start-up Timer (OST) is invoked. However, this is still not a sufficient amount of time to allow the PLL to lock at high frequencies after Unlock MCU.

The PWRT timer is used to provide an additional fixed 2 ms (nominal) time-out to allow the PLL ample time to lock to the incoming clock frequency if Unlock MCU.


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