PIC18F248-E/L MICROCHIP [Microchip Technology], PIC18F248-E/L Datasheet - Page 322

• Manufacturer Part Number: PIC18F248-E/L
• Description: 28/40-Pin High-Performance, Enhanced Flash Microcontrollers with CAN Module
• Manufacturer: MICROCHIP [Microchip Technology]

TBLWT
Syntax:
Operands:
Operation:
Status Affected: None
Encoding:
Description:
DS41159E-page 320
PIC18FXX8
Table Write
[ label ]
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.)
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
0000
TBLPTR[0] = 0:
TBLPTR[0] = 1:
TBLWT ( *; *+; *-; +*)
Holding Register;
Holding Register;
Holding Register;
Holding Register;
0000
TBLPTR;
TBLPTR;
TBLPTR;
Least Significant Byte
of Program Memory
Word
Most Significant Byte
of Program Memory
Word
0000
nn=0 *
11nn
=1 *+
=2 *-
=3 +*
TBLWT Table Write (Continued)
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)
operation
Decode
Q1
No
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)
No operation
operation
TABLAT)
(Read
Q2
No
TBLWT
TBLWT
© 2006 Microchip Technology Inc.
*+;
+*;
operation
operation
Q3
=
=
=
=
=
=
=
=
=
=
=
=
=
=
No
No
0x55
0x00A356
0xFF
0x55
0x00A357
0x55
0x34
0x01389A
0xFF
0xFF
0x34
0x01389B
0xFF
0x34
(Write to Holding
No operation
operation
Register)
Q4
No