12F508 Microchip Technology, 12F508 Datasheet - Page 17

• Manufacturer Part Number: 12F508
• Description: Search -----> PIC12F508
• Manufacturer: Microchip Technology

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4.0
The PIC12F508/509/16F505 memories are organized
into program memory and data memory. For devices
with more than 512 bytes of program memory, a paging
scheme is used. Program memory pages are accessed
using one Status register bit. For the PIC12F509 and
PIC16F505, with data memory register files of more
than 32 registers, a banking scheme is used. Data
memory banks are accessed using the File Select
Register (FSR).
4.1
The PIC12F508 device has a 10-bit Program Counter
(PC) and PIC12F509 has a 11-bit Program Counter
(PC) capable of addressing a 2K x 12 program memory
space.
Only the first 512 x 12 (0000h-01FFh) for the
PIC12F508, and 1K x 12 (0000h-03FFh) for the
PIC12F509
Figure 4-1). Accessing a location above these
boundaries will cause a wraparound within the first
512 x 12 space (PIC12F508) or 1K x 12 space
(PIC12F509). The effective Reset vector is a 0000h
(see Figure 4-1). Location 01FFh (PIC12F508) and
location 03FFh (PIC12F509) contain the internal
clock oscillator calibration value. This value should
never be overwritten.
© 2005 Microchip Technology Inc.
MEMORY ORGANIZATION
Program Memory Organization for
the PIC12F508/509
are
physically
implemented
(see
Preliminary
PIC12F508/509/16F505
FIGURE 4-1:
Note 1:
CALL, RETLW
Address 0000h becomes the
effective Reset vector. Location
01FFh, 03FFh (PIC12F508,
PIC12F509) contains the MOVLW XX
internal oscillator calibration value.
On-chip Program
On-chip Program
Reset Vector
Stack Level 1
Stack Level 2
1024 Word
PROGRAM MEMORY MAP
AND STACK FOR THE
PIC12F508/509
PC<11:0>
512 Word
Memory
Memory
(1)
12
DS41236B-page 15
7FFh
0000h
01FFh
0200h
03FFh
0400h