Encrypted Microcontroller PIC18F8390 Code Extraction needs to disable the protection fuse bit over MCU PIC18F8390 and dump the embedded heximal file out from microprocessor pic18f8390;
When a shutdown occurs, the output pins are asynchronously placed in their shutdown states, specified by the PSSAC1:PSSAC0 and PSSBD1:PSSBD0 bits (ECCPAS2:ECCPAS0). Each pin pair (P1A/P1C and P1B/P1D) may be set to drive high, drive low or be tristated (not driving). The ECCPASE bit (ECCP1AS<7>) is also set to hold the enhanced PWM outputs in their shutdown states before IC’s program has been extracted.
The ECCPASE bit is set by hardware when a shutdown event occurs. If automatic restarts are not enabled, the ECCPASE bit is cleared by firmware when the cause of the shutdown clears. If automatic restarts are enabled, the ECCPASE bit is automatically cleared when the cause of the auto-shutdown has cleared.
If the ECCPASE bit is set when a PWM period begins, the PWM outputs remain in their shutdown state for that entire PWM period. When the ECCPASE bit is cleared, the PWM outputs will return to normal operation at the beginning of the next PWM period when extract code from MCU.
The auto-shutdown feature can be configured to allow automatic restarts of the module following a shutdown event. This is enabled by setting the PRSEN bit of the PWM1CON register (PWM1CON<7>). In Shutdown mode with PRSEN = 1 (Figure 16-10), the ECCPASE bit will remain set for as long as the cause of the shutdown continues. When the shutdown condition clears, the ECCP1ASE bit is cleared. If PRSEN = 0 (Figure 16-11), once a shutdown condition occurs, the ECCPASE bit will remain set until it is cleared by firmware if the firmware of chip can be extracted.
Once ECCPASE is cleared, the enhanced PWM will resume at the beginning of the next PWM period. Independent of the PRSEN bit setting, if the autoshutdown source is one of the comparators, the shutdown condition is a level by reverse engineering Microcontroller. The ECCPASE bit cannot be cleared as long as the cause of the shutdown persists. The Auto-Shutdown mode can be forced by writing a ‘1’ to the ECCPASE bit.
