
2009 Microchip Technology Inc.
DS39755C-page 35
PIC18F2423/2523/4423/4523
3.0
SPECIAL FEATURES OF THE
CPU
3.1
Device ID Registers
The Device ID registers are read-only registers. They
identify the device type and revision for device pro-
grammers and can be read by firmware using table
reads.
TABLE 3-1:
DEVICE IDs
Note:
For additional details on the Configuration
bits, refer to Section 23.1 “Configuration
Bits” in the “PIC18F2420/2520/4420/4520
Data Sheet” (DS39631). Device ID informa-
tion presented in this section is for the
PIC18F2423/2523/4423/4523 devices only.
File Name
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
Default/
Unprogrammed
Value
DEV3
DEV2
DEV1
DEV0
REV3
REV2
REV1
REV0
xxxx xxxx(2)
DEV11
DEV10
DEV9
DEV8
DEV7
DEV6
DEV5
DEV4
xxxx xxxx(2)
Legend:
x = unknown, u = unchanged, — = unimplemented. Shaded cells are unimplemented, read as ‘0’.
Note 1:
DEVID registers are read-only and cannot be programmed by the user.
2:
REGISTER 3-1:
DEVID1: DEVICE ID REGISTER 1 FOR PIC18F2423/2523/4423/4523
RR
R
DEV3
DEV2
DEV1
DEV0
REV3
REV2
REV1
REV0
bit 7
bit 0
Legend:
R = Read-only bit
P = Programmable bit
U = Unimplemented bit, read as ‘0’
-n = Value when device is unprogrammed
u = Unchanged from programmed state
bit 7-4
DEV<3:0>: Device ID bits
1101 = PIC18F4423
1001 = PIC18F4523
0101 = PIC18F2423
0001 = PIC18F2523
bit 3-0
REV<3:0>: Revision ID bits
These bits are used to indicate the device revision.