Microchip Technology MA180025 Data Sheet
2010 Microchip Technology Inc.
DS39933D-page 281
PIC18F87J90 FAMILY
FIGURE 20-2:
ASYNCHRONOUS TRANSMISSION
FIGURE 20-3:
ASYNCHRONOUS TRANSMISSION (BACK TO BACK)
TABLE 20-4:
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
PIR3
—
LCDIF
RC2IF
TX2IF
CTMUIF
CCP2IF
CCP1IF
RTCCIF
62
PIE3
—
LCDIE
RC2IE
TX2IE
CTMUIE
CCP2IE
CCP1IE
RTCCIE
IPR3
—
LCDIP
RC2IP
TX2IP
CTMUIP
CCP2IP
CCP1IP
RTCCIP
RCSTA2
SPEN
RX9
SREN
CREN
ADDEN
FERR
OERR
RX9D
TXREG2
AUSART Transmit Register
TXSTA2
CSRC
TX9
TXEN
SYNC
—
BRGH
TRMT
TX9D
SPBRG2
AUSART Baud Rate Generator Register
LATG
U2OD
U1OD
—
LATG4
LATG3
LATG2
LATG1
LATG0
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 T
CY
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 T
CY
1 T
CY
Start bit