Datasheet

 1996 Microchip Technology Inc. DS30412C-page 139
PIC17C4X
TABLWT
Table Write
Example1
:
TABLWT 0, 1, REG
Before Instruction
REG = 0x53
TBLATH = 0xAA
TBLATL = 0x55
TBLPTR = 0xA356
MEMORY(TBLPTR) = 0xFFFF
After Instruction (table write completion)
REG = 0x53
TBLATH = 0x53
TBLATL = 0x55
TBLPTR = 0xA357
MEMORY(TBLPTR - 1) = 0x5355
Example 2:
TABLWT 1, 0, REG
Before Instruction
REG = 0x53
TBLATH = 0xAA
TBLATL = 0x55
TBLPTR = 0xA356
MEMORY(TBLPTR) = 0xFFFF
After Instruction (table write completion)
REG = 0x53
TBLATH = 0xAA
TBLATL = 0x53
TBLPTR = 0xA356
MEMORY(TBLPTR) = 0xAA53
Program
Memory
16 bits
15 0
TBLPTR
TBLAT
Data
Memory
8 bits
15 8
70
TLRD Table Latch Read
Syntax: [
label ] TLRD t,f
Operands: 0 ≤ f ≤ 255
t ∈ [0,1]
Operation: If t = 0,
TBLATL → f;
If t = 1,
TBLATH → f
Status Affected: None
Encoding:
1010 00tx ffff ffff
Description:
Read data from 16-bit table latch
(TBLAT) into file register 'f'. Table Latch
is unaffected.
If t = 1; high byte is read
If t = 0; low byte is read
This instruction is used in conjunction
with TABLRD to transfer data from pro-
gram memory to data memory.
Words: 1
Cycles: 1
Q Cycle Activity:
Q1 Q2 Q3 Q4
Decode Read
register
TBLATH or
TBLATL
Execute Write
register 'f'
Example:
TLRD t, RAM
Before Instruction
t=0
RAM = ?
TBLAT = 0x00AF (TBLATH = 0x00)
(TBLATL = 0xAF)
After Instruction
RAM = 0xAF
TBLAT = 0x00AF (TBLATH = 0x00)
(TBLATL = 0xAF)
Before Instruction
t=1
RAM = ?
TBLAT = 0x00AF (TBLATH = 0x00)
(TBLATL = 0xAF)
After Instruction
RAM = 0x00
TBLAT = 0x00AF (TBLATH = 0x00)
(TBLATL = 0xAF)
Program
Memory
16 bits
15 0
TBLPTR
TBLAT
Data
Memory
8 bits
15 8
70