 2010 Microchip Technology Inc.

DS39991A-page 19

PIC24FXXKA2XX

3.9

Reading Configuration Memory

The procedure for reading a Configuration register is

the same as reading the code memory. The only

difference is that the 16-bit data words are read (with

the upper byte read being all ‘0‘s) instead of the 24-bit

words. There are eight Configuration registers and they

are read, one register at a time.

Table 3-10 provides the ICSP programming details for

reading all of the Configuration registers.

Note:

The

TBLPAG

register

should

be

hard-coded to 0xF8 (the upper byte

address of the Configuration register) and

the Read Pointer, W6, is initialized to

0x00h.

TABLE 3-10:

SERIAL INSTRUCTION EXECUTION FOR READING ALL THE CONFIGURATION

REGISTERS

Command

(Binary)

Data

(Hex)

Description

Step 1: Exit Reset vector.

0000

0000

0000

000000

040200

000000

NOP

GOTO

0x200

NOP

Step 2: Initialize TBLPAG, the Read Pointer (W6) and the Write Pointer (W7) for TBLRD instruction.

0000

0000

0000

0000

0000

200F80

880190

200007

207847

000000

MOV

#0xF8, W0

MOV

W0, TBLPAG

MOV

#0x0000,W6

MOV

#VISI, W7

NOP

Step 3:

Read the Configuration register and write it to the VISI register (located at 784h), and clock out the

VISI register using the REGOUT command.

0000

0000

0000

0001

BA0BB6

000000

000000

<VISI>

TBLRDL

[W6++], [W7]

NOP

NOP

Clock out contents of VISI register.

Step 4: Repeat Step 3 to read other fuses. Load W6 with their respective address.

Step 5: Reset device internal PC.

0000

0000

040200

000000

GOTO

0x200

NOP