Microchip Technology DM164130-9 User Manual
PICkit™ 3 Starter Kit User’s Guide
DS41628B-page 26
2012 Microchip Technology Inc.
2.12.4
Revision ID
There are five bits in each PIC MCU that indicate the silicon revision of the PIC device.
These bits are read-only and found in the DEVID register. There are usually multiple
revisions of silicon for each PIC device. The errata document, which points out any
errors and their temporary work-arounds, should be read alongside the data sheet.
The PIC18 has a program bus that is 21 bits wide, whereas the enhanced core is only
15 bits wide. A larger program bus infers that the program memory is larger, since it
allows the core to locate a higher address value. The enhanced core program counter
is capable of addressing 32K x 14 program memory space as seen in
These bits are read-only and found in the DEVID register. There are usually multiple
revisions of silicon for each PIC device. The errata document, which points out any
errors and their temporary work-arounds, should be read alongside the data sheet.
The PIC18 has a program bus that is 21 bits wide, whereas the enhanced core is only
15 bits wide. A larger program bus infers that the program memory is larger, since it
allows the core to locate a higher address value. The enhanced core program counter
is capable of addressing 32K x 14 program memory space as seen in
.
FIGURE 2-6:
ENHANCED MID-RANGE PROGRAM MEMORY MAP AND
CALL STACK
CALL STACK
. PIC18 devices also have two interrupt vectors, whereas the enhanced
PIC devices only have one. A stark difference is that the PIC18 has no concept of
pages, whereas the enhanced core has its program memory split into different pages.
pages, whereas the enhanced core has its program memory split into different pages.
PC<14:0>
15
0000h
0004H
Stack Level 0
Stack Level 15
Reset Vector
Interrupt Vector
Stack Level 1
0005h
On-chip
Program
Memory
Page 0
07FFh
Rollover to Page 0
0800h
0FFFh
1000h
1000h
7FFFh
Page 1
Rollover to Page 3
Page 2
Page 3
17FFh
1800h
1800h
1FFFh
2000h
2000h
CALL, CALLW
RETURN, RETLW
Interrupt, RETFIE