PIC18F2682-I/PT MICROCHIP [Microchip Technology], PIC18F2682-I/PT Datasheet - Page 404

• Manufacturer Part Number: PIC18F2682-I/PT
• Description: 28/40/44-Pin Enhanced Flash Microcontrollers with ECAN Technology, 10-Bit A/D and nanoWatt Technology
• Manufacturer: MICROCHIP [Microchip Technology]

PIC18F2682/2685/4682/4685
TBLWT
Syntax:
Operands:
Operation:
Status Affected: None
Encoding:
Description:
Words:
Cycles:
Q Cycle Activity:
DS39761B-page 402
This instruction uses the 3 LSBs of the
1
Table Write
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
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-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
2
operation
Decode
0000
TBLPTR[0] = 0: Least Significant Byte
TBLPTR[0] = 1: Most Significant Byte of
Q1
No
operation
operation
TABLAT)
(Read
0000
Q2
No
No
of Program Memory
Word
Program Memory Word
operation
operation
0000
Q3
No
No
nn=0 *
Register )
operation
operation
(Write to
Holding
=1 *+
=2 *-
=3 +*
11nn
Q4
No
No
Preliminary
TBLWT
Example 1:
Example 2:
Before Instruction
After Instructions (table write completion)
Before Instruction
After Instruction (table write completion)
TABLAT
TBLPTR
HOLDING REGISTER
(00A356h)
TABLAT
TBLPTR
HOLDING REGISTER
(00A356h)
TABLAT
TBLPTR
HOLDING REGISTER
(01389Ah)
HOLDING REGISTER
(01389Bh)
TABLAT
TBLPTR
HOLDING REGISTER
(01389Ah)
HOLDING REGISTER
(01389Bh)
Table Write (Continued)
TBLWT *+;
TBLWT +*;
© 2007 Microchip Technology Inc.
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55h
00A356h
FFh
55h
00A357h
55h
34h
01389Ah
FFh
FFh
34h
01389Bh
FFh
34h