PIC18F258-ESLASHLSQTP datasheet(321/402 Pages) MICROCHIP

321 / 402 page

DS41159E-page 319

PIC18FXX8

TBLRD

Table Read

Syntax:

[

label ]

TBLRD ( *; *+; *-; +*)

Operands:

None

Operation:

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

Status Affected: None

Encoding:

0000

10nn

nn=0 *

=1 *+

=2 *-

=3 +*

Description:

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 Program

Memory Word

TBLPTR[0] = 1:

Most Significant Byte

of Program Memory

Word

The TBLRD instruction can modify the value

of TBLPTR as follows:

• no change

• post-increment

• post-decrement

• pre-increment

Words:

Cycles:

Q Cycle Activity:

Decode

operation

No operation

(Read Program

Memory)

operation

No operation

(Write

TABLAT)

Example 1:

TBLRD

*+ ;

Before Instruction

TABLAT

0x55

TBLPTR

0x00A356

MEMORY(0x00A356)

0x34

After Instruction

TABLAT

0x34

TBLPTR

0x00A357

Example 2:

TBLRD

+* ;

Before Instruction

TABLAT

0xAA

TBLPTR

0x01A357

MEMORY(0x01A357)

0x12

MEMORY(0x01A358)

0x34

After Instruction

TABLAT

0x34

TBLPTR

0x01A358

PIC18F258-E/LSQTP Datasheet(PDF) 321 Page - Microchip Technology

PIC18F258-E/LSQTP Datasheet(HTML) 321 Page - Microchip Technology

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 ...More

Datasheet Download

Link URL