Datasheet

ManualsBrandsMICROCHIP TECHNOLOGY ManualsMicrocontrollers, Microprocessors & QuartzesEmbedded microcontroller TQFP 64 (10x10) 16-Bit 32 MHz I/O number 51

PIC24FJXXXGA1/GB1

3.9 Reading Configuration Words

The procedure for reading configuration memory is

similar to the procedure for reading code memory,

except that 16-bit data words are read (with the upper

byte read being all ‘0’s) instead of 24-bit words.

Configuration Words are read one register at a time.

Table 3-10 shows the ICSP programming details for

reading the Configuration Words. Note that the

TBLPAG register must be loaded with 00h for 64 Kbyte

and below devices and 01h for 128 Kbyte and larger

devices (the upper byte address of configuration mem-

ory), and the Read Pointer, W6, is initialized to the

lower 16 bits of the Configuration Word location.

TABLE 3-10: SERIAL INSTRUCTION EXECUTION FOR READING ALL CONFIGURATION MEMORY

Command

(Binary)

Data

(Hex)

Description

Step 1: Exit Reset vector.

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

200xx0

880190

2xxxx7

207847

000000

MOV <CW3Address23:16>, W0

MOV W0, TBLPAG

MOV <CW3Address15:0>, 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

0001

0000

BA0BB6

000000

<VISI>

000000

TBLRDL [W6++], [W7]

NOP

Clock out contents of VISI register

NOP

Step 4: Repeat Step 3 twice to read Configuration Word 2 and Configuration Word 1.

Step 5: Reset device internal PC.

0000

040200

000000

GOTO 0x200

NOP