16F84A Microchip Technology, 16F84A Datasheet - Page 5

• Manufacturer Part Number: 16F84A
• Description: 18-pin Enhanced Flash/EEPROM 8-Bit Microcontroller
• Manufacturer: Microchip Technology

2.0
There are two memory blocks in the PIC16F84A.
These are the program memory and the data memory.
Each block has its own bus, so that access to each
block can occur during the same oscillator cycle.
The data memory can further be broken down into the
general purpose RAM and the Special Function
Registers (SFRs). The operation of the SFRs that
control the “core” are described here. The SFRs used
to control the peripheral modules are described in the
section discussing each individual peripheral module.
The data memory area also contains the data
EEPROM memory. This memory is not directly mapped
into the data memory, but is indirectly mapped. That is,
an indirect address pointer specifies the address of the
data EEPROM memory to read/write. The 64 bytes of
data EEPROM memory have the address range
0h-3Fh. More details on the EEPROM memory can be
found in Section 5.0.
Additional information on device memory may be found
in the PICmicro™ Mid-Range Reference Manual,
(DS33023).
2.1
The PIC16FXX has a 13-bit program counter capable
of addressing an 8K x 14 program memory space.
For the PIC16F84A, the first 1K x 14 (0000h-03FFh)
are physically implemented (Figure 2-1). Accessing a
location above the physically implemented address will
cause a wraparound. For example, for locations 20h,
420h, 820h, C20h, 1020h, 1420h, 1820h, and 1C20h
will be the same instruction.
The reset vector is at 0000h and the interrupt vector is
at 0004h.
1998 Microchip Technology Inc.
MEMORY ORGANIZATION
Program Memory Organization
Preliminary
FIGURE 2-1:
CALL, RETURN
RETFIE, RETLW
Peripheral Interrupt Vector
PROGRAM MEMORY MAP
AND STACK - PIC16F84A
Stack Level 1
Stack Level 8
Reset Vector
PC<12:0>
PIC16F84A
13
DS35007A-page 5
1FFFh
0000h
0004h
3FFh