PIC18F6390 Datasheet, PDF (199/412 Pages) Microchip Technology – 64/80-Pin Flash Microcontrollers with LCD Driver and nanoWatt Technology

PIC18F6390/6490/8390/8490
16.0 ENHANCED UNIVERSAL
SYNCHRONOUS
ASYNCHRONOUS RECEIVER
TRANSMITTER (EUSART)
PIC18F6390/6490/8390/8490 devices have three
serial I/O modules: the MSSP module, discussed in the
previous chapter and two Universal Synchronous
Asynchronous Receiver Transmitter (USART) mod-
ules. (Generically, the USART is also known as a Serial
Communications Interface or SCI.) The USART 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.
There are two distinct implementations of the USART
module in these devices: the Enhanced USART
(EUSART) discussed here and the Addressable
USART discussed in the next chapter. For this device
family, USART1 always refers to the EUSART, while
USART2 is always the AUSART.
The EUSART and AUSART modules implement the
same core features for serial communications; their
basic operation is essentially the same. The EUSART
module provides additional features, including auto-
matic baud rate detection and calibration, automatic
wake-up on Sync Break reception and 12-bit Break
character transmit. These features 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:
- 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 the EUSART are multiplexed with the func-
tions of PORTC (RC6/TX1/CK1 and RC7/RX1/DT1). In
order to configure these pins as an EUSART:
• bit SPEN (RCSTA1<7>) must be set (= 1)
• bit TRISC<7> must be set (= 1)
• bit TRISC<6> must be set (= 1)
Note:
The USART control will automatically
reconfigure the pin from input to output as
needed.
The operation of the Enhanced USART module is
controlled through three registers:
• Transmit Status and Control Register 1 (TXSTA1)
• Receive Status and Control Register 1 (RCSTA1)
• Baud Rate Control Register 1 (BAUDCON1)
The registers are described in Register 16-1,
Register 16-2 and Register 16-3.
 2004 Microchip Technology Inc.
Preliminary
DS39629B-page 197