PIC12F508/509/16F505
4.2
Program Memory Organization
For The PIC16F505
4.3
Data Memory Organization
Data memory is composed of registers or bytes of
RAM. Therefore, data memory for a device is specified
by its register file. The register file is divided into two
functional groups: Special Function Registers (SFR)
and General Purpose Registers (GPR).
The PIC16F505 device has a 11-bit Program Counter
(PC) capable of addressing a 2K x 12 program memory
space.
The 1K x 12 (0000h-03FFh) for the PIC16F505 are
physically implemented. Refer to Figure 4-2. Access-
ing a location above this boundary will cause a wrap-
around within the first 1K x 12 space. The effective
Reset vector is at 0000h (see Figure 4-2). Location
03FFh contains the internal oscillator calibration value.
This value should never be overwritten.
The Special Function Registers include the TMR0 reg-
ister, the Program Counter (PCL), the STATUS register,
the I/O registers (ports) and the File Select Register
(FSR). In addition, Special Function Registers are used
to control the I/O port configuration and prescaler
options.
The General Purpose Registers are used for data and
control information under command of the instructions.
FIGURE 4-2:
PROGRAM MEMORY MAP
AND STACK FOR THE
PIC16F505
For the PIC12F508/509, the register file is composed of
7 Special Function Registers, 9 General Purpose
Registers and 16 or 32 General Purpose Registers
accessed by banking (see Figure 4-3 and Figure 4-4).
PC<11:0>
12
CALL, RETLW
For the PIC16F505, the register file is composed of 8
Stack Level 1
Stack Level 2
Special Function Registers,
8 General Purpose
Registers and 64 General Purpose Registers accessed
by banking (Figure 4-5).
(1)
Reset Vector
0000h
4.3.1
GENERAL PURPOSE REGISTER
FILE
The General Purpose Register file is accessed, either
directly or indirectly, through the File Select Register
(FSR). See Section 4.9 “Indirect Data Addressing:
INDF and FSR Registers”.
01FFh
0200h
On-chip Program
Memory
1024 Words
03FFh
0400h
7FFh
Note 1: Address 0000h becomes the
effective Reset vector. Location
03FFh contains the MOVLW XX
internal oscillator calibration value.
DS41236C-page 16
Preliminary
© 2007 Microchip Technology Inc.
MICROCHIP [ MICROCHIP ]
