PIC18F2420/2520/4420/4520
1.2
Other Special Features
1.3
•
Memory Endurance:
The Enhanced Flash cells
for both program memory and data EEPROM are
rated to last for many thousands of erase/write
cycles – up to 100,000 for program memory and
1,000,000 for EEPROM. Data retention without
refresh is conservatively estimated to be greater
than 40 years.
•
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 PIC18F2420/
2520/4420/4520 family introduces an optional
extension to the PIC18 instruction set, which adds
8 new instructions and an Indexed Addressing
mode. This extension, enabled as a device con-
figuration option, has been specifically designed
to optimize re-entrant application code originally
developed in high-level languages, such as C.
•
Enhanced CCP Module:
In PWM mode, this
module provides 1, 2 or 4 modulated outputs for
controlling half-bridge and full-bridge drivers.
Other features include auto-shutdown, for dis-
abling PWM outputs on interrupt, or other select
conditions, and auto-restart to reactivate outputs
once the condition has cleared.
•
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. When the
microcontroller is using the internal oscillator
block, the EUSART provides stable operation for
applications that talk to the outside world without
using an external crystal (or its accompanying
power requirement).
•
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.
•
Extended Watchdog Timer (WDT):
This
enhanced version incorporates a 16-bit prescaler,
allowing an extended time-out range that is stable
across operating voltage and temperature. See
for
time-out periods.
Details on Individual Family
Members
Devices in the PIC18F2420/2520/4420/4520 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 five
ways:
1.
Flash program memory (16 Kbytes for
PIC18F2420/4420 devices and 32 Kbytes for
PIC18F2520/4520 devices).
A/D channels (10 for 28-pin devices, 13 for
40/44-pin devices).
I/O ports (3 bidirectional ports on 28-pin devices,
5 bidirectional ports on 40/44-pin devices).
CCP and Enhanced CCP implementation
(28-pin devices have 2 standard CCP
modules, 40/44-pin devices have one standard
CCP module and one ECCP module).
Parallel Slave Port (present only on 40/44-pin
devices).
2.
3.
4.
5.
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
Like all Microchip PIC18 devices, members of the
PIC18F2420/2520/4420/4520 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 PIC18F2420),
accommodate an operating V
DD
range of 4.2V to 5.5V.
Low-voltage parts, designated by “LF” (such as
PIC18LF2420), function over an extended V
DD
range
of 2.0V to 5.5V.
DS39631E-page 8
©
2008 Microchip Technology Inc.
MICROCHIP [ MICROCHIP TECHNOLOGY ]
