PIC18F23K22 Datasheet, PDF (406/492 Pages) Microchip Technology – 28/40/44-Pin, Low-Power, High-Performance Microcontrollers with nanoWatt XLP Technology

PIC18(L)F2X/4XK22
TBLWT
Table Write
Syntax:
TBLWT ( *; *+; *-; +*)
Operands:
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 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.
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
Words:
1
Cycles:
2
Q Cycle Activity:
Q1
Q2
Q3
Q4
Decode No
No
No
operation operation operation
No
No
No
No
operation operation operation operation
(Read
(Write to
TABLAT)
Holding
Register )
TBLWT
Table Write (Continued)
Example1:
TBLWT *+;
Before Instruction
TABLAT
=
TBLPTR
=
HOLDING REGISTER
(00A356h)
=
55h
00A356h
FFh
After Instructions (table write completion)
TABLAT
=
TBLPTR
=
HOLDING REGISTER
(00A356h)
=
55h
00A357h
55h
Example 2:
TBLWT +*;
Before Instruction
TABLAT
=
TBLPTR
=
HOLDING REGISTER
(01389Ah)
=
HOLDING REGISTER
(01389Bh)
=
34h
01389Ah
FFh
FFh
After Instruction (table write completion)
TABLAT
=
TBLPTR
=
HOLDING REGISTER
(01389Ah)
=
HOLDING REGISTER
(01389Bh)
=
34h
01389Bh
FFh
34h
DS41412B-page 406
Preliminary
 2010 Microchip Technology Inc.