PIC18C242 MICROCHIP [Microchip Technology], PIC18C242 Datasheet - Page 232

• Manufacturer Part Number: PIC18C242
• Description: High-Performance Microcontrollers with 10-Bit A/D
• Manufacturer: MICROCHIP [Microchip Technology]

PIC18CXX2
TBLWT
Syntax:
Operands:
Operation:
Status Affected:
Encoding:
Description:
Words:
Cycles:
Q Cycle Activity:
DS39026B-page 232
operation
Decode
No
Q1
operation
operation
TABLAT)
(Read
Table Write
[ label ]
None
if TBLWT*,
(TABLAT)
Holding Register;
TBLPTR - No Change;
if TBLWT*+,
(TABLAT)
Holding Register;
(TBLPTR) +1
if TBLWT*-,
(TABLAT)
Holding Register;
(TBLPTR) -1
if TBLWT+*,
(TBLPTR) +1
(TABLAT)
Holding Register;
None
This instruction is used to program the
contents of Program Memory (P.M.).
The TBLPTR (a 21-bit pointer) points
to each byte in the program memory.
TBLPTR has a 2 MBtye address
range. The LSb of the TBLPTR
selects which byte of the program
memory location to access.
The TBLWT instruction can modify the
value of TBLPTR as follows:
• no change
• post-increment
• post-decrement
• pre-increment
1
2 (many if long write is to on-chip
EPROM program memory)
No
No
Q2
0000
TBLPTR[0] = 0:Least Significant
TBLPTR[0] = 1:Most
operation
operation
TBLWT ( *; *+; *-; +*)
No
No
Prog Mem (TBLPTR) or
Prog Mem (TBLPTR) or
Prog Mem (TBLPTR) or
Prog Mem (TBLPTR) or
0000
Q3
TBLPTR;
TBLPTR;
TBLPTR;
Register or Memory)
(Write to Holding
0000
Byte of Program
Memory Word
Byte of Program
Memory Word
operation
operation
No
No
Significant
Q4
nn=0 *
11nn
=1 *+
=2 *-
=3 +*
Preliminary
TBLWT
Example1:
Example 2:
Before Instruction
After Instructions (table write completion)
Before Instruction
After Instruction (table write completion)
TABLAT
TBLPTR
MEMORY(0x00A356)
TABLAT
TBLPTR
MEMORY(0x00A356)
TABLAT
TBLPTR
MEMORY(0x01389A)
MEMORY(0x01389B)
TABLAT
TBLPTR
MEMORY(0x01389A)
MEMORY(0x01389B)
Table Write (cont.’d)
TBLWT
TBLWT
7/99 Microchip Technology Inc.
*+;
+*;
=
=
=
=
=
=
=
=
=
=
=
=
=
=
0x55
0x00A356
0xFF
0x55
0x00A357
0x55
0x34
0x01389A
0xFF
0xFF
0x34
0x01389B
0xFF
0x34