PIC18F87K22 Datasheet, PDF (468/548 Pages) Microchip Technology – 64/80-Pin, High-Performance, 1-Mbit Enhanced Flash Microcontrollers with 12-Bit A/D and nanoWatt XLP Technology

PIC18F87K22 FAMILY
TBLWT
Table Write
Syntax:
Operands:
Operation:
Status Affected:
Encoding:
Description:
TBLWT ( *; *+; *-; +*)
None
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
None
0000 0000 0000
11nn
nn=0 *
=1 *+
=2 *-
=3 +*
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 “Memory
Organization” 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.
Words:
Cycles:
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
1
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)
Example 1:
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
DS39960B-page 468
Preliminary
 2010 Microchip Technology Inc.