PIC18F2480_09 Datasheet, PDF (242/490 Pages) Microchip Technology – 28/40/44-Pin Enhanced Flash Microcontrollers with ECAN Technology, 10-Bit A/D and nanoWatt Technology

PIC18F2480/2580/4480/4580
FIGURE 19-3:
EUSART TRANSMIT BLOCK DIAGRAM
TXIE
TXIF
Interrupt
MSb
(8)
Data Bus
TXREG Register
8
LSb
•••
0
TSR Register
Pin Buffer
and Control
TXEN Baud Rate CLK
BRG16
SPBRGH SPBRG
Baud Rate Generator
TX9
TX9D
TRMT
SPEN
TX Pin
FIGURE 19-4:
Write to TXREG
BRG Output
(Shift Clock)
TX
(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 19-5:
ASYNCHRONOUS TRANSMISSION (BACK-TO-BACK)
Write to TXREG
BRG Output
(Shift Clock)
TX
(pin)
TXIF bit
(Interrupt Reg. Flag)
TRMT bit
(Transmit Shift
Reg. Empty Flag)
Word 1
Word 2
Start bit
bit 0
1 TCY
Word 1
Transmit Shift Reg.
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.
DS39637D-page 242
© 2009 Microchip Technology Inc.