12C509 Просмотр технического описания (PDF) - Microchip Technology
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12C509 Datasheet PDF : 113 Pages
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4.0 MEMORY ORGANIZATION
PIC12C5XX memory is organized into program mem-
ory 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 STA-
TUS register bit. For the PIC12C509, PIC12C509A,
PICCR509A and PIC12CE519 with a data memory
register file of more than 32 registers, a banking
scheme is used. Data memory banks are accessed
using the File Select Register (FSR).
4.1 Program Memory Organization
The PIC12C5XX devices have a 12-bit Program
Counter (PC) capable of addressing a 2K x 12
program memory space.
Only the first 512 x 12 (0000h-01FFh) for the
PIC12C508, PIC12C508A and PIC12CE518 and 1K x
12 (0000h-03FFh) for the PIC12C509, PIC12C509A,
PIC12CR509A, and PIC12CE519 are physically
implemented. Refer to Figure 4-1. Accessing a
location above these boundaries will cause a wrap-
around within the first 512 x 12 space (PIC12C508,
PIC12C508A and PIC12CE518) or 1K x 12 space
(PIC12C509, PIC12C509A, PIC12CR509A and
PIC12CE519). The effective reset vector is at 000h,
(see Figure 4-1). Location 01FFh (PIC12C508,
PIC12C508A and PIC12CE518) or location 03FFh
(PIC12C509, PIC12C509A, PIC12CR509A and
PIC12CE519) contains the internal clock oscillator
calibration value. This value should never be
overwritten.
PIC12C5XX
FIGURE 4-1: PROGRAM MEMORY MAP
AND STACK
PC<11:0>
CALL, RETLW
12
Stack Level 1
Stack Level 2
Reset Vector (note 1)
0000h
On-chip Program
Memory
512 Word
On-chip Program
Memory
1024 Word
01FFh
0200h
03FFh
0400h
7FFh
Note 1: Address 0000h becomes the
effective reset vector. Location
01FFh (PIC12C508, PIC12C508A,
PIC12CE518) or location 03FFh
(PIC12C509, PIC12C509A,
PIC12CR509A, PIC12CE519) con-
tains the MOVLW XX INTERNAL RC
oscillator calibration value.
© 1999 Microchip Technology Inc.
DS40139E-page 13
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