PCM18XT0 Microchip Technology, PCM18XT0 Datasheet - Page 63

• Manufacturer Part Number: PCM18XT0
• Description: MODULE PROC PIC18F4685
• Manufacturer: Microchip Technology

Specifications of PCM18XT0

• Accessory Type: Processor Module
• Product: Microcontroller Modules
• Core Processor: PIC18F4685
• Lead Free Status / RoHS Status: Not applicable / Not applicable
• For Use With/related Products: ICE2000
• For Use With: ICE2000 - EMULATOR MPLAB-ICE 2000 POD
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant, Not applicable / Not applicable

5.0
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”.
FIGURE 5-1:
© 2009 Microchip Technology Inc.
CALL, RCALL, RETURN
RETFIE, RETLW
MEMORY ORGANIZATION
High Priority Interrupt Vector 00008h
Low Priority Interrupt Vector
PIC18F2682/4682
Program Memory
Stack Level 31
Stack Level 1
Reset Vector
PC<20:0>
Read ‘0’
On-Chip
PROGRAM MEMORY MAP AND STACK FOR PIC18F2682/2685/4682/4685 DEVICES
•
•
•
21
0000h
0018h
13FFFh
14000h
1FFFFFh
200000h
PIC18F2682/2685/4682/4685
CALL, RCALL, RETURN
RETFIE, RETLW
5.1
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).
The PIC18F2682 and PIC18F4682 each have 80 Kbytes
of Flash memory and can store up to 40,960 single-word
instructions. The PIC18F2685 and PIC18F4685 each
have 96 Kbytes of Flash memory and can store up to
49,152 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 PIC18F2682/4682 and
PIC18F2685/4685 devices are shown in Figure 5-1.
High Priority Interrupt Vector 0008h
Low Priority Interrupt Vector
Program Memory Organization
PIC18F2685/4685
Program Memory
Stack Level 31
Stack Level 1
Reset Vector
PC<20:0>
On-Chip
Read ‘0’
•
•
•
21
0000h
0018h
17FFFh
18000h
1FFFFFh
200000h
DS39761C-page 63