June 2017

SECTION III-4: File Register Instructions Using FileReg or WREG as Destination

Table below operate on the file register only and then give you the option of placing the result in WREG or a file register location.


SECTION III-2: Instructions involving the WREG and the Access Bank

You cannot move literal (immediate) values directly into the general purpose RAM locations in the PIC18. They must be moved there via WREG.

SECTION III-1: MOVWF Instruction in the PIC micro-controller

The PIC allows direct access to other locations in the file register for ALU and other operations. In this section we show the instructions using various locations of the file register.

MOVWF Instruction:-

SECTION II-5: File Register and Access bank in the PIC18

The file register of the PIC18 family can have a maximum of 4096 (4K) bytes. With 4096 bytes, the file register has addresses of 000-FFFH. The file register in the PIC18 is divided into 256 byte banks. We can have up to a maximum of 16 banks (16 X 256 = 4096). Although not all members of the PIC18 family have that many banks, every PIC18 family member has at least one bank for the file register. This bank is called the access bank and is the default bank when we power up the PIC18 chip.

SECTION II-4: General Purpose Registers RAM Vs EEPROM in PIC micro-controller

There are two RAM columns in the chip information section of the Microchip website. One refers to the general purpose registers GP RAM size, and the other is the EEPROM size. GP RAM, which constitutes most of the file register, must not be confused with the EEPROM data memory. The GPRs are used by the CPU for internal data storage, whereas the EEPROMs are considered as an add-on memory that one can also add externally to the chip.

SECTION II-3: General-Purpose Registers or RAM in PIC micro-controller

The general purpose registers are a group of RAM locations in the file register that are used for data storage and scratch pad. Each location is 8 bits wide and can be used to store any data we want as long as it is 8 bit. Again, the number of RAM locations in the file register that are set aside for general purpose registers can vary from chip to chip, even among members of the same family.

SECTION II-2: Special Function Registers in PIC micro-controller

The Special Function Register (SFRs) are dedicated to specific functions such as ALU status, timers, serial communication, I/O ports, ADC and so on. The function of each SFR is fixed by the CPU designer at the time of design because it is used for control of the micro-controller or peripheral. The PIC SFRs are 8 bit registers. The number of locations in the file register set aside for SFR depends on the pin numbers and peripheral functions supported by that chip.


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