PIC18F2221 MICROCHIP [Microchip Technology], PIC18F2221 Datasheet - Page 207

• Manufacturer Part Number: PIC18F2221
• Description: 28/40/44-Pin Enhanced Flash Microcontrollers with 10-Bit A/D and nanoWatt Technology
• Manufacturer: MICROCHIP [Microchip Technology]

18.0
The Enhanced Universal Synchronous Asynchronous
Receiver Transmitter (EUSART) module is one of the
two serial I/O modules. (Generically, the USART is also
known as a Serial Communications Interface or SCI.)
The EUSART can be configured as a full-duplex
asynchronous system that can communicate with
peripheral devices, such as CRT terminals and
personal computers. It can also be configured as a half-
duplex synchronous system that can communicate
with peripheral devices, such as A/D or D/A integrated
circuits, serial EEPROMs, etc.
The Enhanced USART module implements additional
features, including automatic baud rate detection and
calibration, automatic wake-up on Sync Break recep-
tion and 12-bit Break character transmit. These make it
ideally suited for use in Local Interconnect Network bus
(LIN bus) systems.
The EUSART can be configured in the following
modes:
• Asynchronous (full duplex) with:
• Synchronous – Master (half duplex) with
• Synchronous – Slave (half duplex) with selectable
© 2007 Microchip Technology Inc.
- Auto-wake-up on Break signal
- Auto-baud calibration
- 12-bit Break character transmission
selectable clock polarity
clock polarity
ENHANCED UNIVERSAL
SYNCHRONOUS
ASYNCHRONOUS RECEIVER
TRANSMITTER (EUSART)
Preliminary
The pins of the Enhanced USART are multiplexed
with PORTC. In order to configure RC6/TX/CK and
RC7/RX/DT as an EUSART:
• bit SPEN (RCSTA<7>) must be set (= 1)
• bit TRISC<7> must be set (= 1)
• bit TRISC<6> must be set (= 1)
The operation of the Enhanced USART module is
controlled through three registers:
• Transmit Status and Control (TXSTA)
• Receive Status and Control (RCSTA)
• Baud Rate Control (BAUDCON)
These are detailed on the following pages in
Register 18-1,
respectively.
PIC18F4321 FAMILY
Note:
The EUSART control will automatically
reconfigure the pin from input to output as
needed.
Register 18-2
and
DS39689E-page 205
Register 18-3,