PIC18F1220 MICROCHIP [Microchip Technology], PIC18F1220 Datasheet - Page 231

• Manufacturer Part Number: PIC18F1220
• Description: 18/20/28-Pin High-Performance, Enhanced Flash Microcontrollers with 10-bit A/D and nanoWatt Technology
• Manufacturer: MICROCHIP [Microchip Technology]

TBLRD
Syntax:
Operands:
Operation:
Status Affected: None
Encoding:
Description:
Words:
Cycles:
 2004 Microchip Technology Inc.
Q Cycle Activity:
operation
Decode
Q1
No
[ label ] 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
Table Read
(Read Program
No operation
0000
operation
Memory)
TBLPTR[0] = 0: Least Significant
TBLPTR[0] = 1: Most Significant
Q2
No
0000
operation
operation
TBLPTR;
TBLPTR;
TBLPTR;
Q3
No
No
0000
Byte of Program
Memory Word
Byte of Program
Memory Word
TABLAT;
TABLAT;
TABLAT;
TABLAT;
No operation
nn = 0*
operation
TABLAT)
(Write
10nn
Q4
No
= 1*+
= 2*-
= 3+*
TBLRD
Example 1:
Example 2:
Before Instruction
After Instruction
Before Instruction
After Instruction
TABLAT
TBLPTR
MEMORY(0x00A356)
TABLAT
TBLPTR
TABLAT
TBLPTR
MEMORY(0x01A357)
MEMORY(0x01A358)
TABLAT
TBLPTR
PIC18F1220/1320
Table Read (Continued)
TBLRD
TBLRD
*+ ;
+* ;
=
=
=
=
=
=
=
=
=
=
=
DS39605C-page 229
0x55
0x00A356
0x34
0x34
0x00A357
0xAA
0x01A357
0x12
0x34
0x34
0x01A358