Datasheet

PIC18F2450/4450
DS39760D-page 8 © 2008 Microchip Technology Inc.
1.2 Other Special Features
• Memory Endurance: The Enhanced Flash cells
for program memory are rated to last for many
thousands of erase/write cycles – up to 100,000.
• Self-Programmability: These devices can write
to their own program memory spaces under
internal software control. By using a bootloader
routine, located in the protected Boot Block at the
top of program memory, it becomes possible to
create an application that can update itself in the
field.
• Extended Instruction Set: The PIC18F2450/
4450 family introduces an optional extension to
the PIC18 instruction set, which adds 8 new
instructions and an Indexed Literal Offset
Addressing mode. This extension, enabled as a
device configuration option, has been specifically
designed to optimize re-entrant application code
originally developed in high-level languages such
as C.
• Enhanced Addressable USART: This serial
communication module is capable of standard
RS-232 operation and provides support for the LIN
bus protocol. Other enhancements include
Automatic Baud Rate Detection and a 16-bit Baud
Rate Generator for improved resolution.
• 10-Bit A/D Converter: This module incorporates
programmable acquisition time, allowing for a
channel to be selected and a conversion to be
initiated, without waiting for a sampling period and
thus, reducing code overhead.
• Dedicated ICD/ICSP Port: These devices
introduce the use of debugger and programming
pins that are not multiplexed with other micro-
controller features. Offered as an option in select
packages, this feature allows users to develop I/O
intensive applications while retaining the ability to
program and debug in the circuit.
1.3 Details on Individual Family
Members
Devices in the PIC18F2450/4450 family are available
in 28-pin and 40/44-pin packages. Block diagrams for
the two groups are shown in Figure 1-1 and Figure 1-2.
The devices are differentiated from each other in the
following two ways:
1. A/D channels (10 for 28-pin devices, 13 for
40/44-pin devices).
2. I/O ports (3 bidirectional ports and 1 input only
port on 28-pin devices, 5 bidirectional ports on
40/44-pin devices).
All other features for devices in this family are identical.
These are summarized in Table 1-1.
The pinouts for all devices are listed in Table 1-2 and
Table 1-3.
Like all Microchip PIC18 devices, members of the
PIC18F2450/4450 family are available as both standard
and low-voltage devices. Standard devices with
Enhanced Flash memory, designated with an “F” in the
part number (such as PIC18F2450), accommodate an
operating V
DD range of 4.2V to 5.5V. Low-voltage parts,
designated by “LF” (such as PIC18LF2450), function
over an extended VDD range of 2.0V to 5.5V.