PIC18F25J50 MICROCHIP [Microchip Technology], PIC18F25J50 Datasheet - Page 473

• Manufacturer Part Number: PIC18F25J50
• Description: 28/44-Pin, Low-Power, High-Performance USB Microcontrollers with nanoWatt XLP Technology
• Manufacturer: MICROCHIP [Microchip Technology]

TBLRD
Syntax:
Operands:
Operation:
Status Affected: None
Encoding:
Description:
Words:
Cycles:
 2011 Microchip Technology Inc.
Q Cycle Activity:
operation
Decode
No
Q1
(Read Program
Table Read
TBLRD ( *; *+; *-; +*)
None
if TBLRD *,
(Prog Mem (TBLPTR))  TABLAT,
TBLPTR – No Change;
if TBLRD *+,
(Prog Mem (TBLPTR))  TABLAT,
(TBLPTR) + 1  TBLPTR;
if TBLRD *-,
(Prog Mem (TBLPTR))  TABLAT,
(TBLPTR) – 1  TBLPTR;
if TBLRD +*,
(TBLPTR) + 1  TBLPTR,
(Prog Mem (TBLPTR))  TABLAT
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.
TBLPTR<0> = 0: Least Significant Byte of
TBLPTR<0> = 1: Most Significant Byte of
The TBLRD instruction can modify the
value of TBLPTR as follows:
• no change
• post-increment
• post-decrement
• pre-increment
1
2
No operation
operation
Memory)
0000
No
Q2
0000
operation
operation
Program Memory Word
Program Memory Word
No
No
Q3
0000
No operation
operation
TABLAT)
(Write
nn=0 *
No
Q4
10nn
=1 *+
=2 *-
=3 +*
PIC18F46J50 FAMILY
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
Table Read (Continued)
TBLRD
TBLRD
*+
+*
=
=
=
=
=
=
=
=
=
=
=
DS39931D-page 473
55h
00A356h
34h
34h
00A357h
AAh
01A357h
12h
34h
34h
01A358h