PIC18F1230 MICROCHIP [Microchip Technology], PIC18F1230 Datasheet - Page 247

• Manufacturer Part Number: PIC18F1230
• Description: 18/20/28-Pin, Enhanced Flash Microcontrollers with nanoWatt Technology, High-Performance PWM and A/D
• Manufacturer: MICROCHIP [Microchip Technology]

TBLRD
Syntax:
Operands:
Operation:
Status Affected: None
Encoding:
Description:
Words:
Cycles:
© 2006 Microchip Technology Inc.
Q Cycle Activity:
operation
Decode
Q1
No
Table Read
TBLRD ( *; *+; *-; +*)
None
if TBLRD *
(Prog Mem (TBLPTR))
TBLPTR – No Change;
if TBLRD *+
(Prog Mem (TBLPTR))
(TBLPTR) + 1
if TBLRD *-
(Prog Mem (TBLPTR))
(TBLPTR) – 1
if TBLRD +*
(TBLPTR) + 1
(Prog Mem (TBLPTR))
This instruction is used to read the contents
of Program Memory (P.M.). To address the
program memory, a pointer called Table
Pointer (TBLPTR) is used.
The TBLPTR (a 21-bit pointer) points to
each byte in the program memory. TBLPTR
has a 2-Mbyte address range.
The TBLRD instruction can modify the value
of TBLPTR as follows:
• no change
• post-increment
• post-decrement
• pre-increment
1
2
(Read Program
TBLPTR[0] = 0: Least Significant Byte of
TBLPTR[0] = 1: Most Significant Byte of
No operation
0000
operation
Memory)
Q2
No
0000
TBLPTR;
TBLPTR;
TBLPTR;
Program Memory Word
Program Memory Word
operation
operation
Q3
No
No
0000
TABLAT;
TABLAT;
TABLAT;
TABLAT
No operation
Advance Information
operation
TABLAT)
nn=0 *
(Write
10nn
Q4
No
=1 *+
=2 *-
=3 +*
TBLRD
Example 1:
Example 2:
Before Instruction
After Instruction
Before Instruction
After Instruction
TABLAT
TBLPTR
MEMORY (00A356h)
TABLAT
TBLPTR
TABLAT
TBLPTR
MEMORY (01A357h)
MEMORY (01A358h)
TABLAT
TBLPTR
PIC18F1230/1330
Table Read (Continued)
TBLRD
TBLRD
*+ ;
+* ;
=
=
=
=
=
=
=
=
=
=
=
DS39758B-page 245
55h
00A356h
34h
00A357h
AAh
01A357h
34h
01A358h
34h
12h
34h