PIC18F4321 Datasheet, PDF (10/396 Pages) Microchip Technology – 28/40/44-Pin Enhanced Flash Microcontrollers with 10-Bit A/D and nanoWatt Technology

PIC18F4321 FAMILY
1.2 Other Special Features
• 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 PIC18F4321
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 configuration
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
disabling 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
Section 26.0 “Electrical Characteristics” for
time-out periods.
• 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 PIC18F4321 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 (4 Kbytes for
PIC18F2221/4221 devices, 8 Kbytes for
PIC18F2321/4321).
2. A/D channels (10 for 28-pin devices, 13 for
40/44-pin devices).
3. I/O ports (3 bidirectional ports on 28-pin devices,
5 bidirectional ports on 40/44-pin devices).
4. 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).
5. Parallel Slave Port (present only 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
PIC18F4321 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 PIC18F2321), accommodate an
operating VDD range of 4.2V to 5.5V. Low-voltage
parts, designated by “LF” (such as PIC18LF2321),
function over an extended VDD range of 2.0V to 5.5V.
DS39689E-page 8
Preliminary
© 2007 Microchip Technology Inc.