PIC18F1220 MICROCHIP [Microchip Technology], PIC18F1220 Datasheet - Page 232

• Manufacturer Part Number: PIC18F1220
• Description: 18/20/28-Pin High-Performance, Enhanced Flash Microcontrollers with 10-bit A/D and nanoWatt Technology
• Manufacturer: MICROCHIP [Microchip Technology]

PIC18F1220/1320
TBLWT
Syntax:
Operands:
Operation:
Status Affected: None
Encoding:
Description:
DS39605C-page 230
[ label ] TBLWT ( *; *+; *-; +*)
None
if TBLWT*,
(TABLAT)
TBLPTR – No Change;
if TBLWT*+,
(TABLAT)
(TBLPTR) + 1
if TBLWT*-,
(TABLAT)
(TBLPTR) – 1
if TBLWT+*,
(TBLPTR) + 1
(TABLAT)
This instruction uses the 3 LSBs of
TBLPTR to determine which of the
8 holding registers the TABLAT is
written to. The holding registers are
used to program the contents of
Program Memory (P.M.). (Refer
to Section 6.0 “Flash Program
Memory” 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.
The TBLWT instruction can modify the
value of TBLPTR as follows:
• no change
• post-increment
• post-decrement
• pre-increment
Table Write
0000
TBLPTR[0] = 0:Least Significant
TBLPTR[0] = 1:Most Significant
0000
Holding Register;
Holding Register;
Holding Register;
Holding Register;
TBLPTR;
TBLPTR;
TBLPTR;
0000
Byte of Program
Memory Word
Byte of Program
Memory Word
nn = 0*
11nn
= 1*+
= 2*-
= 3+*
TBLWT
Words: 1
Cycles: 2
Q Cycle Activity:
Example 1:
Example 2:
Before Instruction
After Instructions (table write completion)
Before Instruction
After Instruction (table write completion)
TABLAT
TBLPTR
HOLDING REGISTER
(0x00A356)
TABLAT
TBLPTR
HOLDING REGISTER
(0x00A356)
TABLAT
TBLPTR
HOLDING REGISTER
(0x01389A)
HOLDING REGISTER
(0x01389B)
TABLAT
TBLPTR
HOLDING REGISTER
(0x01389A)
HOLDING REGISTER
(0x01389B)
operation
Decode
Q1
No
TBLWT *+;
TBLWT +*;
Table Write (Continued)
operation
operation
TABLAT)
 2004 Microchip Technology Inc.
(Read
Q2
No
No
=
=
=
=
=
=
=
=
=
=
=
=
=
=
operation
operation
0x55
0x00A356
0xFF
0x55
0x00A357
0x55
0x34
0x01389A
0xFF
0xFF
0x34
0x01389B
0xFF
0x34
Q3
No
No
operation
operation
Register)
(Write to
Holding
Q4
No
No