PIC12F1822 MICROCHIP [Microchip Technology], PIC12F1822 Datasheet - Page 19

• Manufacturer Part Number: PIC12F1822
• Description: 8/14-Pin Flash Microcontrollers with nanoWatt XLP Technology
• Manufacturer: MICROCHIP [Microchip Technology]

2.0
This family of devices contain an enhanced mid-range
8-bit CPU core. The CPU has 49 instructions. Interrupt
capability includes automatic context saving. The
hardware stack is 16 levels deep and has Overflow and
Underflow Reset capability. Direct, Indirect, and
Relative addressing modes are available. Two File
Select Registers (FSRs) provide the ability to read
program and data memory.
• Automatic Interrupt Context Saving
• 16-level Stack with Overflow and Underflow
• File Select Registers
• Instruction Set
2.1
During interrupts, certain registers are automatically
saved in shadow registers and restored when returning
from the interrupt. This saves stack space and user
code. See Section 8.5 “Automatic Context Saving”,
for more information.
2.2
These devices have an external stack memory 15 bits
wide and 16 words deep. A Stack Overflow or Under-
flow will set the appropriate bit (STKOVF or STKUNF)
in the PCON register, and if enabled will cause a soft-
ware Reset. See section Section 3.4 “Stack” for more
details.
2.3
There are two 16-bit File Select Registers (FSR). FSRs
can access all file registers and program memory,
which allows one data pointer for all memory. When an
FSR points to program memory, there is 1 additional
instruction cycle in instructions using INDF to allow the
data to be fetched. General purpose memory can now
also be addressed linearly, providing the ability to
access contiguous data larger than 80 bytes. There are
also new instructions to support the FSRs. See
Section 3.5 “Indirect Addressing” for more details.
2.4
There are 49 instructions for the enhanced mid-range
CPU to support the features of the CPU. See
Section 28.0 “Instruction Set Summary” for more
details.
 2010 Microchip Technology Inc.
ENHANCED MID-RANGE CPU
Automatic Interrupt Context
Saving
16-level Stack with Overflow and
Underflow
File Select Registers
Instruction Set
PIC12F/LF1822/16F/LF1823
Preliminary
DS41413A-page 19