Datasheet

Table Of Contents
2010 Microchip Technology Inc. DS39770C-page 263
PIC18F85J90 FAMILY
FIGURE 19-2: ASYNCHRONOUS TRANSMISSION
FIGURE 19-3: ASYNCHRONOUS TRANSMISSION (BACK TO BACK)
TABLE 19-4: 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 57
PIR3
LCDIF RC2IF TX2IF CCP2IF CCP1IF —60
PIE3 LCDIE RC2IE TX2IE CCP2IE CCP1IE —60
IPR3
LCDIP RC2IP TX2IP CCP2IP CCP1IP —60
RCSTA2
SPEN RX9 SREN CREN ADDEN FERR OERR RX9D 62
TXREG2 AUSART Transmit Register 62
TXSTA2
CSRC TX9 TXEN SYNC BRGH TRMT TX9D 62
SPBRG2 AUSART Baud Rate Generator Register 62
LATG U2OD
U1OD LATG4 LATG3 LATG2 LATG1 LATG0 60
Legend: — = unimplemented locations read as ‘0’. Shaded cells are not used for asynchronous transmission.
Word 1
Word 1
Transmit Shift Reg
Start bit bit 0 bit 1 bit 7/8
Write to TXREG2
BRG Output
(Shift Clock)
TX2 (pin)
TX2IF bit
(Transmit Buffer
Reg. Empty Flag)
TRMT bit
(Transmit Shift
Reg. Empty Flag)
1 TCY
Word 1
Stop bit
Transmit Shift Reg.
Write to TXREG2
BRG Output
(Shift Clock)
TX2 (pin)
TX2IF bit
(Interrupt Reg. Flag)
TRMT bit
(Transmit Shift
Reg. Empty Flag)
Word 1
Word 2
Word 1
Word 2
Stop bit
Start bit
Transmit Shift Reg.
Word 1
Word 2
bit 0 bit 1
bit 7/8 bit 0
Note: This timing diagram shows two consecutive transmissions.
1 TCY
1 TCY
Start bit