PIC18C658 MICROCHIP [Microchip Technology], PIC18C658 Datasheet - Page 259

• Manufacturer Part Number: PIC18C658
• Description: High-Performance Microcontrollers with CAN Module
• Manufacturer: MICROCHIP [Microchip Technology]

22.4
If the code protection bit(s) have not been pro-
grammed, the on-chip program memory can be read
out for verification purposes.
22.5
Five memory locations (200000h - 200004h) are desig-
nated as ID locations, where the user can store check-
sum or other code identification numbers. These
locations are accessible during normal execution
through the TBLRD instruction, or during program/ver-
ify. The ID locations can be read when the device is
code protected.
REGISTER 22-7:
REGISTER 22-8:
Note:
2000 Microchip Technology Inc.
Program Verification/Code Protection
ID Locations
Microchip Technology does not recom-
mend code protecting windowed devices.
bit 7-5
bit 4-0
bit 7-0
DEVID1 ID REGISTER FOR THE PIC18CXX8 DEVICE (0x3FFFFE)
DEVID2 ID REGISTER FOR THE PIC18CXX8 DEVICE (0x3FFFFF)
Legend:
R = Readable bit
U = Unimplemented bit, read as ‘0’
Legend:
R = Readable bit
U = Unimplemented bit, read as ‘0’
bit 7
DEV2:DEV0: Device ID bits
These bits are used with the DEV10:DEV3 bits in the Device ID register 2
to identify the part number
REV4:REV0: Revision ID bits
These bits are used to indicate the revision of the device
bit 7
DEV10:DEV3: Device ID bits
These bits are used with the DEV2:DEV0 bits in the Device ID register 1
to identify the part number
DEV10
DEV2
R/P-1
R/P-1
R/P-1
DEV1
R/P-1
DEV9
Advanced Information
DEV0
DEV8
R/P-1
R/P-1
R/P-1
REV4
R/P-1
DEV7
22.6
PIC18CXX8 microcontrollers can be serially pro-
grammed while in the end application circuit. This is
simply done with two lines for clock and data, and three
other lines for power, ground and the programming
voltage. This allows customers to manufacture boards
with unprogrammed devices, and then program the
microcontroller just before shipping the product. This
also allows the most recent firmware or a custom firm-
ware to be programmed.
22.7
Device ID bits are located in program memory at
3FFFFEh and 3FFFFFh. The Device ID bits are used
by programmers to retrieve part number and revision
information about a device. These registers may also
be accessed using a TBLRD instruction (Register 22-8
and Register 22-7).
P = Programmable bit
P = Programmable bit
- n = Unprogrammed Value
- n = Unprogrammed Value
(x = unknown)
(x = unknown)
In-Circuit Serial Programming
Device ID Bits
REV3
DEV6
R/P-1
R/P-1
R/P-1
REV2
R/P-1
DEV5
PIC18CXX8
R/P-1
REV1
R/P-1
DEV4
DS30475A-page 259
R/P-1
REV0
R/P-1
DEV3
bit 0
bit 0