PIC18F2450 MICROCHIP [Microchip Technology], PIC18F2450 Datasheet - Page 252

• Manufacturer Part Number: PIC18F2450
• Description: 28/40/44-Pin, High-Performance, 12 MIPS, Enhanced Flash, USB Microcontrollers with nanoWatt Technology
• Manufacturer: MICROCHIP [Microchip Technology]

PIC18F2450/4450
TBLWT
Syntax:
Operands:
Operation:
Status Affected: None
Encoding:
Description:
Words:
Cycles:
Q Cycle Activity:
DS39760A-page 250
Table Write
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
1
2
operation
Decode
0000
TBLPTR[0] = 0: Least Significant Byte of
TBLPTR[0] = 1: Most Significant Byte of
Q1
No
operation
operation
TABLAT)
(Read
0000
Holding Register;
Holding Register;
Holding Register;
Holding Register
Q2
No
No
TBLPTR;
TBLPTR;
TBLPTR;
Program Memory Word
Program Memory Word
operation
operation
0000
Q3
No
No
Advance Information
nn=0 *
operation
operation
Register)
(Write to
Holding
=1 *+
=2 *-
=3 +*
11nn
Q4
No
No
TBLWT
Example 1:
Example 2:
Before Instruction
After Instructions (table write completion)
Before Instruction
After Instruction (table write completion)
TABLAT
TBLPTR
HOLDING REGISTER
TABLAT
TBLPTR
HOLDING REGISTER
TABLAT
TBLPTR
HOLDING REGISTER
HOLDING REGISTER
TABLAT
TBLPTR
HOLDING REGISTER
HOLDING REGISTER
(00A356h)
(00A356h)
(01389Bh)
(01389Ah)
(01389Bh)
(01389Ah)
Table Write (Continued)
TBLWT
TBLWT
© 2006 Microchip Technology Inc.
*+;
+*;
=
=
=
=
=
=
=
=
=
=
=
=
=
=
55h
00A356h
FFh
55h
00A357h
55h
34h
01389Ah
FFh
FFh
34h
01389Bh
FFh
34h