Datasheet

Table Of Contents
2010 Microchip Technology Inc. Preliminary DS39979A-page 249
PIC18F87J72 FAMILY
FIGURE 19-4: ASYNCHRONOUS TRANSMISSION
FIGURE 19-5: ASYNCHRONOUS TRANSMISSION (BACK TO BACK)
TABLE 19-5: 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 RC1IF TX1IF SSPIF TMR2IF TMR1IF 52
PIE1 ADIE RC1IE TX1IE SSPIE TMR2IE TMR1IE 52
IPR1
ADIP RC1IP TX1IP SSPIP TMR2IP TMR1IP 52
RCSTA1 SPEN RX9 SREN CREN ADDEN FERR OERR RX9D 51
TXREG1 EUSART Transmit Register 51
TXSTA1
CSRC TX9 TXEN SYNC SENDB BRGH TRMT TX9D 51
BAUDCON1 ABDOVF RCMT RXDTP TXCKP BRG16 WUE ABDEN 53
SPBRGH1 EUSART Baud Rate Generator Register High Byte 53
SPBRG1 EUSART Baud Rate Generator Register Low Byte 51
LATG
U2OD U1OD LATG4 LATG3 LATG2 LATG1 LATG0 52
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 TXREG1
BRG Output
(Shift Clock)
TX1 (pin)
TX1IF bit
(Transmit Buffer
Reg. Empty Flag)
TRMT bit
(Transmit Shift
Reg. Empty Flag)
1 TCY
Word 1
Stop bit
Transmit Shift Reg.
Write to TXREG1
BRG Output
(Shift Clock)
TX1 (pin)
TX1IF 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