PIC18F45K20-E/P Microchip Technology, PIC18F45K20-E/P Datasheet - Page 13

• Manufacturer Part Number: PIC18F45K20-E/P
• Description: 32KB, Flash, 1536bytes-RAM, 36I/O, 8-bit Family,nanowatt XLP 40 PDIP .600in TUBE
• Manufacturer: Microchip Technology
• Series: PIC® XLP™ 18Fr

Specifications of PIC18F45K20-E/P

• Core Processor: PIC
• Core Size: 8-Bit
• Speed: 48MHz
• Connectivity: I²C, SPI, UART/USART
• Peripherals: Brown-out Detect/Reset, HLVD, POR, PWM, WDT
• Number Of I /o: 35
• Program Memory Size: 32KB (16K x 16)
• Program Memory Type: FLASH
• Eeprom Size: 256 x 8
• Ram Size: 1.5K x 8
• Voltage - Supply (vcc/vdd): 1.8 V ~ 3.6 V
• Data Converters: A/D 14x10b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 125°C
• Package / Case: 40-DIP (0.600", 15.24mm)
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• For Use With: DM240313 - BOARD DEMO 8BIT XLPAC164112 - VOLTAGE LIMITER MPLAB ICD2 VPPDM164124 - KIT STARTER FOR PIC18F4XK20
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

2.1
2.2
© 2009 Microchip Technology Inc.
Chapter 2. PIC18FXXXX Microcontroller Architectural
MEMORY ORGANIZATION
PROGRAM MEMORY
This section provides a simple overview of the PIC18FXXXX microcontroller
architecture.
The PIC18FXXXX microcontrollers are Harvard architecture microprocessors, mean-
ing that program memory and data memory are in separate spaces. This allows faster
execution as the program and data busses are separate and dedicated, so one bus
does not have to be used for both memory types. The return address stack also has its
own dedicated memory.
The program memory space is addressed by a 21-bit Program Counter (PC), allowing
a 2 Mb program memory space. Typically, PIC18FXXXX microcontrollers have on-chip
program memory in the range of 4K to 128 Kbytes. Some devices allow external
memory expansion.
At Reset, the PC is set to zero and the first instruction is fetched. Interrupt vectors are
at locations 0x000008 and 0x000018, so a GOTO instruction is usually placed at
address zero to jump over the interrupt vectors.
Most instructions are 16 bits, but some are double word 32-bit instructions. Instructions
cannot be executed on odd numbered bytes.
These are some important characteristics of the PIC18C architecture and MPLAB C
Compiler capabilities with reference to program memory:
MPLAB C Compiler Implementation
Refer to the “MPLAB C18 C Compiler User’s Guide” (DS51288) for more information
on these features.
• Instructions are typically stored in program memory with the section attribute
• Data can be stored in program memory with the section attribute romdata in con-
• MPLAB C Compiler can be configured to generate code for two memory models,
PIC18 Architecture
In some PIC18XXXX devices, program memory or portions of program memory can be
code-protected. Code will execute properly but it cannot be read out or copied.
Program memory can be read using table read instructions, and can be written through
a special code sequence using the table write instruction.
code.
junction with the rom keyword.
small and large. When using the small memory model, pointers to program mem-
ory use 16 bits. The large model uses 24-bit pointers.
Overview
PICkit™ 3 DEBUG EXPRESS
DS41370C-page 9