PIC18F6X2X Datasheet, PDF (318/386 Pages) Microchip Technology – 64/80-Pin High Performance, 64-Kbyte Enhanced FLASH Microcontrollers with A/D

PIC18F6X2X/8X2X
TBLWT
Table Write
Syntax:
Operands:
[ label ] TBLWT ( *; *+; *-; +*)
None
Operation:
if TBLWT*,
(TABLAT) → Holding Register;
TBLPTR - No Change;
if TBLWT*+,
(TABLAT) → Holding Register;
(TBLPTR) +1 → TBLPTR;
if TBLWT*-,
(TABLAT) → Holding Register;
(TBLPTR) -1 → TBLPTR;
if TBLWT+*,
(TBLPTR) +1 → TBLPTR;
(TABLAT) → Holding Register;
Status Affected: None
Encoding:
0000
0000
0000
11nn
nn=0 *
=1 *+
=2 *-
=3 +*
Description:
This instruction uses the 3 LSBs of
TBLPTR to determine which of the 8
holding registers the TABLAT is writ-
ten to. The holding registers are used
to program the contents of Program
Memory (P.M.). (Refer to Section 5.0
for additional details on programming
FLASH memory.)
The TBLPTR (a 21-bit pointer) points
to each byte in the program memory.
TBLPTR has a 2-MByte address
range. The LSb of the TBLPTR
selects which byte of the program
memory location to access.
TBLPTR[0] = 0: Least Significant
Byte of Program
Memory Word
TBLPTR[0] = 1: Most Significant
Byte of Program
Memory Word
The TBLWT instruction can modify
the value of TBLPTR as follows:
• no change
• post-increment
• post-decrement
• pre-increment
TBLWT Table Write (Continued)
Words: 1
Cycles: 2
Q Cycle Activity:
Q1
Q2
Q3
Decode
No
operation
No
operation
No
operation
(Read
TABLAT)
No
operation
No
operation
Q4
No
operation
No
operation
(Write to
Holding
Register )
Example1:
TBLWT *+;
Before Instruction
TABLAT
=
TBLPTR
=
HOLDING REGISTER
(0x00A356)
=
0x55
0x00A356
0xFF
After Instructions (table write completion)
TABLAT
=
TBLPTR
=
HOLDING REGISTER
(0x00A356)
=
0x55
0x00A357
0x55
Example 2:
TBLWT +*;
Before Instruction
TABLAT
=
TBLPTR
=
HOLDING REGISTER
(0x01389A)
=
HOLDING REGISTER
(0x01389B)
=
0x34
0x01389A
0xFF
0xFF
After Instruction (table write completion)
TABLAT
=
TBLPTR
=
HOLDING REGISTER
(0x01389A)
=
HOLDING REGISTER
(0x01389B)
=
0x34
0x01389B
0xFF
0x34
DS39612A-page 316
Advance Information
 2003 Microchip Technology Inc.