PIC18F2450_08 Datasheet, PDF (166/324 Pages) Microchip Technology – 28/40/44-Pin, High-Performance, 12 MIPS, Enhanced Flash, USB Microcontrollers with nanoWatt Technology

PIC18F2450/4450
FIGURE 15-4:
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 15-5:
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
1 TCY
Start bit
bit 0
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.
TABLE 15-5: REGISTERS ASSOCIATED WITH ASYNCHRONOUS TRANSMISSION
Name
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
Reset
Values on
Page:
INTCON GIE/GIEH PEIE/GIEL TMR0IE INT0IE RBIE TMR0IF INT0IF RBIF
49
PIR1
—
ADIF
RCIF
TXIF
—
CCP1IF TMR2IF TMR1IF
51
PIE1
—
ADIE
RCIE
TXIE
—
CCP1IE TMR2IE TMR1IE
51
IPR1
—
ADIP
RCIP
TXIP
—
CCP1IP TMR2IP TMR1IP
51
RCSTA
SPEN
RX9
SREN CREN ADDEN FERR OERR RX9D
51
TXREG EUSART Transmit Register
51
TXSTA
CSRC
TX9
TXEN SYNC SENDB BRGH TRMT TX9D
51
BAUDCON ABDOVF RCIDL
—
SCKP BRG16
—
WUE ABDEN
51
SPBRGH EUSART Baud Rate Generator Register High Byte
50
SPBRG EUSART Baud Rate Generator Register Low Byte
50
Legend: — = unimplemented locations read as ‘0’. Shaded cells are not used for asynchronous transmission.
DS39760D-page 164
© 2008 Microchip Technology Inc.