PIC17C752 MICROCHIP [Microchip Technology], PIC17C752 Datasheet - Page 55

• Manufacturer Part Number: PIC17C752
• Description: High-Performance 8-Bit CMOS EPROM Microcontrollers
• Manufacturer: MICROCHIP [Microchip Technology]

8.0
The PIC17C75X has four instructions that allow the
processor to move data from the data memory space
to the program memory space, and vice versa. Since
the program memory space is 16-bits wide and the
data memory space is 8-bits wide, two operations are
required to move 16-bit values to/from the data mem-
ory.
The TLWT t,f and TABLWT t,i,f instructions are
used to write data from the data memory space to the
program memory space. The TLRD t,f and TABLRD
t,i,f instructions are used to write data from the pro-
gram memory space to the data memory space.
The program memory can be internal or external. For
the program memory access to be external, the device
needs to be operating in extended microcontroller or
microprocessor mode.
Figure 8-1 through Figure 8-4 show the operation of
these four instructions.
FIGURE 8-1:
Note 1: 8-bit value, from register 'f', loaded into the
1997 Microchip Technology Inc.
MEMORY
DATA
f
TABLE READS AND TABLE
WRITES
high or low byte in TABLAT (16-bit).
TABLE POINTER
TABLE LATCH (16-bit)
TLWT
1
TBLPTRH
TABLATH
1,f
TLWT INSTRUCTION
OPERATION
TBLPTRL
TABLATL
TLWT
PROGRAM MEMORY
0,f
Preliminary
FIGURE 8-2:
Note 1: 8-bit value, from register 'f', loaded into the
MEMORY
DATA
f
2: 16-bit TABLAT value written to address
3: If “i” = 1, then TBLPTR = TBLPTR + 1,
TABLWT
high or low byte in TABLAT (16-bit).
Program Memory (TBLPTR).
If “i” = 0, then TBLPTR is unchanged.
TABLE POINTER
TABLE LATCH (16-bit)
1
3
1,i,f
TBLPTRH
TABLATH
TABLWT INSTRUCTION
OPERATION
Prog-Mem
(TBLPTR)
2
TBLPTRL
TABLATL
TABLWT
PROGRAM MEMORY
DS30264A-page 55
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0,i,f