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PIC18F6585 Datasheet, PDF (240/496 Pages) Microchip Technology – 64/68/80-Pin High-Performance, 64-Kbyte Enhanced Flash Microcontrollers with ECAN Module
PIC18F6585/8585/6680/8680
FIGURE 18-2:
USART TRANSMIT BLOCK DIAGRAM
TXIE
TXIF
MSb
(8)
Interrupt
TXEN Baud Rate CLK
Data Bus
TXREG Register
8
•••
TSR Register
BRG16
SPBRGH SPBRG
Baud Rate Generator
TX9
TX9D
LSb
0
Pin Buffer
and Control
TRMT
SPEN
RC6/TX/CK pin
FIGURE 18-3:
Write to TXREG
BRG Output
(Shift Clock)
RC6/TX/CK
(pin)
TXIF bit
(Transmit Buffer
Reg. Empty Flag)
TRMT bit
(Transmit Shift
Reg. Empty Flag)
ASYNCHRONOUS TRANSMISSION
Word 1
Start bit
bit 0
1 TCY
bit 1
Word 1
Word 1
Transmit Shift Reg
bit 7/8 Stop bit
FIGURE 18-4:
Write to TXREG
BRG Output
(Shift Clock)
RC6/TX/CK
(pin)
TXIF bit
(Interrupt Reg. Flag)
TRMT bit
(Transmit Shift
Reg. Empty Flag)
ASYNCHRONOUS TRANSMISSION (BACK TO BACK)
Word 1
Word 2
1 TCY
Start bit
Word 1
Transmit Shift Reg.
bit 0
1 TCY
bit 1
Word 1
bit 7/8 Stop bit
Start bit
bit 0
Word 2
Word 2
Transmit Shift Reg.
Note: This timing diagram shows two consecutive transmissions.
DS30491C-page 238
 2004 Microchip Technology Inc.