We can Read Encrypted Microcontroller PIC18F4420 Firmware, please view the Microcontroller PIC18F4420 features for your reference:

Special Function Registers. These are categorized by Power-on and Brown-out Resets, Master Clear and WDT Resets and WDT wake-ups. There are three types of memory in PIC18 Enhanced microcontroller devices:

• Program Memory
• Data RAM
• Data EEPROM

As Harvard architecture devices, the data and program memories use separate busses; this allows for concurrent access of the two memory spaces. The data EEPROM, for practical purposes, can be regarded as a peripheral device, since it is addressed and accessed through a set of control registers.

Additional detailed information on the operation of the Flash program memory is provided in Section 6.0 “Flash Program Memory”. Data EEPROM is discussed separately in Section 7.0 “Data EEPROM Memory”.PIC18 microcontrollers implement a 21-bit program counter, which is capable of addressing a 2-Mbyte program memory space. Accessing a location between the upper boundary of the physically implemented memory and the 2-Mbyte address will return all ‘0’s (a NOP instruction) when Read Encrypted Microcontroller PIC18F4420 Firmware.

The PIC18F4420 has 4 Kbytes of Flash memory and can store up to 2,048 single-word instructions. The PIC18F4420 has 8 Kbytes of Flash memory and can store up to 4,096 single-word instructions. PIC18 devices have two interrupt vectors. The Reset vector address is at 0000h and the interrupt vector addresses are at 0008h and 0018h.

The program memory maps for PIC18F4420 devices are shown in Figure 5-1. The Program Counter (PC) specifies the address of the instruction to fetch for execution. The PC is 21 bits wide and is contained in three separate 8-bit registers. The low byte, known as the PCL register, is both readable and writable. The high byte, or PCH register, contains the PC<15:8> bits; it is not directly readable or writable if Read Encrypted Microcontroller PIC18F4420 Firmware.

Updates to the PCH register are performed through the PCLATH register. The upper byte is called PCU. This register contains the PC<20:16> bits; it is also not directly readable or writable. Updates to the PCU register are performed through the PCLATU register. The contents of PCLATH and PCLATU are transferred to the program counter by any operation that writes to the PCL. Similarly, the upper two bytes of the program counter are transferred to PCLATH and PCLATU by an operation that reads the PCL. This is useful for computed offsets to the PC (see Section 5.1.4.1 “Computed GOTO”) after READ MCU.