PIC16F7X7
The AUSART can be configured in the following
modes:
11.0 ADDRESSABLE UNIVERSAL
SYNCHRONOUS
• Asynchronous (full-duplex)
ASYNCHRONOUS RECEIVER
TRANSMITTER (AUSART)
• Synchronous – Master (half-duplex)
• Synchronous – Slave (half-duplex)
The Addressable Universal Synchronous Asynchronous
Receiver Transmitter (AUSART) module is one of the
two serial I/O modules. (AUSART is also known as a
Serial Communications Interface or SCI.) The AUSART
can be configured as a full-duplex asynchronous system
that can communicate with peripheral devices, such as
CRT terminals and personal computers, or it can 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.
Bit SPEN (RCSTA<7>) and bits TRISC<7:6> have
to be set in order to configure pins RC6/TX/CK and
RC7/RX/DT
as
the
Universal
Synchronous
Asynchronous Receiver Transmitter.
The AUSART module also has a multi-processor
communication capability using 9-bit address detection.
REGISTER 11-1: TXSTA: TRANSMIT STATUS AND CONTROL REGISTER (ADDRESS 98h)
R/W-0
CSRC
R/W-0
TX9
R/W-0
TXEN
R/W-0
SYNC
U-0
—
R/W-0
BRGH
R-1
R/W-0
TX9D
TRMT
bit 7
bit 0
bit 7
CSRC: Clock Source Select bit
Asynchronous mode:
Don’t care.
Synchronous mode:
1= Master mode (clock generated internally from BRG)
0= Slave mode (clock from external source)
bit 6
bit 5
TX9: 9-bit Transmit Enable bit
1= Selects 9-bit transmission
0= Selects 8-bit transmission
TXEN: Transmit Enable bit
1= Transmit enabled
0= Transmit disabled
Note:
SREN/CREN overrides TXEN in Sync mode.
bit 4
SYNC: AUSART Mode Select bit
1= Synchronous mode
0= Asynchronous mode
bit 3
bit 2
Unimplemented: Read as ‘0’
BRGH: High Baud Rate Select bit
Asynchronous mode:
1= High speed
0= Low speed
Synchronous mode:
Unused in this mode.
bit 1
bit 0
TRMT: Transmit Shift Register Status bit
1= TSR empty
0= TSR full
TX9D: 9th bit of Transmit Data, can be Parity bit
Legend:
R = Readable bit
-n = Value at POR
W = Writable bit
‘1’ = Bit is set
U = Unimplemented bit, read as ‘0’
‘0’ = Bit is cleared x = Bit is unknown
2004 Microchip Technology Inc.
DS30498C-page 133
MICROCHIP [ MICROCHIP ]
