PIC 8 BIT AND 16 BIT MICROCONTROLLER ARCHITECTURE

Harvard Architecture

Low - end PIC Architectures Mid-range PIC Architectures The architectures of various PIC microcontrollers can be divided as follows : Low - end PIC Architectures Mid-range PIC Architectures CPU Architecture

Specification of some popular PIC microcontroller are as follows: Basic Architecture of PIC Microcontrollers Specification of some popular PIC microcontroller are as follows:

PIC Microcontroller clock One instruction cycle

PIC 8 bit Architecture

Architecture of PIC 16C74A

W Register- Status Register- STATUS-address 03H,83H CPU Registers: W Register- Status Register- STATUS-address 03H,83H

FSR Register(file selection register,address=04H,84H)- FSR is an 8 bit register used as data memory address pointer. This is used in indirect addressing mode INDF Register(INDirect through FSR,address=00H,80H)- INDF is not a physical register. Accessing INDF access is the location pointed to by FSR in indirect addressing mode

PCL Register-(Program counter low byte,address=02H,82H) PCL is actually the lower 8 bits of the 13-bit program counter. This is both readable and writable register PCLATH register(Program counter Latch,address=0AH,8AH)- PCLATH is a 8 bit register which can be used to decide upper 5 bits of program counter. PCLATH can be read or written to without affecting the program counter

Port Structure

Pin Configuration

PIC 16 bit microcontroller architecture

Pin Diagram:

Architecture of PIC 24H

DATA MEMORY ORGANISATION

STATUS Register : CORCON Register : CPU Registers STATUS Register : CORCON Register :

ALU MULTIPLIER DIVISOR

PIC 8 bit and 16 bit architecture features: Harvard architecture. Small number of fixed length instruction. A hardware stack for storing return address. Data spaced mapped CPU , port and periferal registers.

Limitations Only one accumulator Operations and registers are not orthogonal Register bank switching is required Software implemented stacks are not efficient

Conclusion Thus PIC architecture offers- Again it gives- Seamless migration Pin compatibility Code compatibility Again it gives- Flexibility Maximise reuse for future developments

References www.microchip.com www.viit.ac.in/PIC microcontroller/Y.H.Dandawate,VIIT,Pune nptel.iitm.ac.in/IIT Kanpur/PIC Abhilash V. Pandiankal, Microcontroller system,S.CHAND publication

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