 2010 Microchip Technology Inc.

DS39991A-page 21

PIC24FXXKA2XX

4.0

DEVICE ID

The Device ID region of memory can be used to

determine the mask, variant and manufacturing

information about the device. The Device ID region is

2 x 16 bits and it can be read using the READC

command. This region of memory is read-only and can

also be read when code protection is enabled.

Table 4-1 provides the Device ID for each device;

Table 4-2 provides the Device ID registers; Table 4-3

describes the bit field of each register.

TABLE 4-1:

DEVICE IDs

4.1

Checksums

4.1.1

CHECKSUM COMPUTATION

Checksums for the PIC24FXXKA2XX family are

16 bits. The checksum is calculated by summing the

following:

• Contents of the code memory locations

• Contents of the Configuration registers

Table 4-4 describes how to calculate the checksum for

each device.

All memory locations are summed, one byte at a time,

using only their native data size. More specifically,

Configuration registers are summed by adding the

lower two bytes of these locations (the upper byte is

ignored) while the code memory is summed by adding

all three bytes of the code memory.

TABLE 4-2:

PIC24FXXKA2XX DEVICE ID REGISTERS

Device ID

DEVID

PIC24F04KA200

0D02h

PIC24F04KA201

0D00h

Address

Name

Bit

15

14

13

12

11

10

9876

543210

FF0000h

DEVID

FAMID<7:0>

DEV<7:0>

FF0002h

DEVREV

—

REV<3:0>

TABLE 4-3:

DEVICE ID BITS DESCRIPTION

Bit Field

Register

Description

FAMID<7:0>

DEVID

Encodes the family ID of the device.

DEV<7:0>

DEVID

Encodes the individual ID of the device.

REV<3:0>

DEVREV

Encodes the revision number of the device.

TABLE 4-4:

CHECKSUM COMPUTATION

Device

Read Code Protection

Checksum Computation

Erased

Checksum

Value

Chip Checksum with

0xAAAAAA at 0x00

Location and

at Last Location

PIC24F04KAXXX

Disabled

CFGB + SUM (0:000AFE)

0x74B4

0x72B6

Enabled

0

0x0000

0x0000

Legend: Item

Description

SUM[a:b] =

Byte sum of locations, a to b inclusive (all 3 bytes of code memory)

CFGB

=

Configuration Block (masked),

Byte sum of (FGS & 0x0003 + FOSCSEL & 0x0087 + FOSC & 0x00DF + FWDT & 0x00DF +

FPOR & 0x00FB + FICD & 0x00C3 + FDS & 0x00FF)