PIC18LF2X_13 Datasheet, PDF (412/560 Pages) Microchip Technology – PIC18(L)F2X/45K50 USB Flash MCU Product Brief

PIC18(L)F2X/4XK22
TBLWT
Table Write
Syntax:
TBLWT ( *; *+; *-; +*)
Operands:
None
Operation:
if TBLWT*,
(TABLAT)  Holding Register;
TBLPTR – No Change;
if TBLWT*+,
(TABLAT)  Holding Register;
(TBLPTR) + 1  TBLPTR;
if TBLWT*-,
(TABLAT)  Holding Register;
(TBLPTR) – 1  TBLPTR;
if TBLWT+*,
(TBLPTR) + 1  TBLPTR;
(TABLAT)  Holding Register;
Status Affected: None
Encoding:
0000
0000
0000
11nn
nn=0 *
=1 *+
=2 *-
=3 +*
Description:
This instruction uses the three LSBs of
TBLPTR to determine which of the eight
holding registers the TABLAT is written to.
The holding registers are used to program
the contents of Program Memory (P.M.).
(Refer to Section 6.0 “Flash Program
Memory” for additional details on pro-
gramming Flash memory.)
The TBLPTR (a 21-bit pointer) points to
each byte in the program memory.
TBLPTR has a 2-MByte address range.
The LSb of the TBLPTR selects which
byte of the program memory location to
access.
TBLPTR[0] = 0: Least Significant
Byte of Program
Memory Word
TBLPTR[0] = 1: Most Significant
Byte of Program
Memory Word
The TBLWT instruction can modify the
value of TBLPTR as follows:
• no change
• post-increment
• post-decrement
• pre-increment
Words:
1
Cycles:
2
Q Cycle Activity:
Q1
Q2
Q3
Q4
Decode No
No
No
operation operation operation
No
No
No
No
operation operation operation operation
(Read
(Write to
TABLAT)
Holding
Register )
TBLWT
Table Write (Continued)
Example1:
TBLWT *+;
Before Instruction
TABLAT
=
TBLPTR
=
HOLDING REGISTER
(00A356h)
=
55h
00A356h
FFh
After Instructions (table write completion)
TABLAT
=
TBLPTR
=
HOLDING REGISTER
(00A356h)
=
55h
00A357h
55h
Example 2:
TBLWT +*;
Before Instruction
TABLAT
TBLPTR
= 34h
= 01389Ah
HOLDING REGISTER
(01389Ah)
= FFh
HOLDING REGISTER
(01389Bh)
= FFh
After Instruction (table write completion)
TABLAT
= 34h
TBLPTR
=
HOLDING REGISTER
(01389Ah)
=
HOLDING REGISTER
01389Bh
FFh
(01389Bh)
= 34h
DS41412F-page 412
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