PIC18F44J50-I Datasheet, PDF (323/562 Pages) Microchip Technology – 28/44-Pin, Low-Power, High-Performance USB Microcontrollers

PIC18F46J50 FAMILY
20.0 ENHANCED UNIVERSAL
SYNCHRONOUS
ASYNCHRONOUS RECEIVER
TRANSMITTER (EUSART)
The Enhanced Universal Synchronous Asynchronous
Receiver Transmitter (EUSART) module is one of two
serial I/O modules. (Generically, the EUSART 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 and so on.
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/J2602 bus) systems.
All members of the PIC18F46J50 family are equipped
with two independent EUSART modules, referred to as
EUSART1 and EUSART2. They can be configured in
the following modes:
• Asynchronous (full-duplex) with:
- Auto-wake-up on character reception
- Auto-baud calibration
- 12-bit Break character transmission
• Synchronous – Master (half-duplex) with
selectable clock polarity
• Synchronous – Slave (half-duplex) with selectable
clock polarity
The pins of EUSART1 and EUSART2 are multiplexed
with the functions of PORTC (RC6/TX1/CK1/RP17 and
RC7/RX1/DT1/SDO1/RP18) and remapped
(RPn1/TX2/CK2 and RPn2/RX2/DT2), respectively. In
order to configure these pins as an EUSART:
• For EUSART1:
- SPEN bit (RCSTA1<7>) must be set (= 1)
- TRISC<7> bit must be set (= 1)
- TRISC<6> bit must be cleared (= 0) for
Asynchronous and Synchronous Master
modes
- TRISC<6> bit must be set (= 1) for
Synchronous Slave mode
• For EUSART2:
- SPEN bit (RCSTA2<7>) must be set (= 1)
- TRIS bit for RPn2/RX2/DT2 = 1
- TRIS bit for RPn1/TX2/CK2 = 0 for
Asynchronous and Synchronous Master
modes
- TRISC<6> bit must be set (= 1) for
Synchronous Slave mode
Note:
The EUSART control will automatically
reconfigure the pin from input to output as
needed.
The TXx/CKx I/O pins have an optional open-drain
output capability. By default, when this pin is used by
the EUSART as an output, it will function as a standard
push-pull CMOS output. The TXx/CKx I/O pins’
open-drain, output feature can be enabled by setting
the corresponding UxOD bit in the ODCON2 register.
For more details, see Section 19.3.3 “Open-Drain
Output Option”.
The operation of each Enhanced USART module is
controlled through three registers:
• Transmit Status and Control (TXSTAx)
• Receive Status and Control (RCSTAx)
• Baud Rate Control (BAUDCONx)
These are covered in detail in Register 20-1,
Register 20-2 and Register 20-3, respectively.
Note:
Throughout this section, references to
register and bit names that may be asso-
ciated with a specific EUSART module are
referred to generically by the use of ‘x’ in
place of the specific module number.
Thus, “RCSTAx” might refer to the
Receive Status register for either
EUSART1 or EUSART2.
 2011 Microchip Technology Inc.
DS39931D-page 323