PIC18F6525_13 Datasheet, PDF (222/400 Pages) Microchip Technology – 64/80-Pin High-Performance, 64-Kbyte Enhanced Flash Microcontrollers with A/D

PIC18F6525/6621/8525/8621
FIGURE 19-3:
Write to TXREGx
BRG Output
(Shift Clock)
TXx
(pin)
TXxIF 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 19-4:
ASYNCHRONOUS TRANSMISSION (BACK TO BACK)
Write to TXREGx
BRG Output
(Shift Clock)
TXx
(pin)
TXxIF 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
Note:
This timing diagram shows two consecutive transmissions.
bit 7/8 Stop bit
Start bit
bit 0
Word 2
Word 2
Transmit Shift Reg.
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
Value on
POR, BOR
Value on
all other
Resets
INTCON
PIR1
PIE1
IPR1
GIE/GIEH
PSPIF⁽¹⁾
PSPIE⁽¹⁾
PSPIP⁽¹⁾
PEIE/GIEL TMR0IE INT0IE
ADIF
RC1IF TX1IF
ADIE
RC1IE TX1IE
ADIP
RC1IP TX1IP
RBIE
SSPIF
SSPIE
SSPIP
TMR0IF
CCP1IF
CCP1IE
CCP1IP
INT0IF
TMR2IF
TMR2IE
TMR2IP
RBIF
TMR1IF
TMR1IE
TMR1IP
0000 000x 0000 000u
0000 0000 0000 0000
0000 0000 0000 0000
1111 1111 1111 1111
PIR3
—
—
RC2IF TX2IF TMR4IF CCP5IF CCP4IF CCP3IF --00 0000 --00 0000
PIE3
—
—
RC2IE TX2IE TMR4IE CCP5IE CCP4IE CCP3IE --00 0000 --00 0000
IPR3
—
—
RC2IP TX2IP TMR4IP CCP5IP CCP4IP CCP3IP --11 1111 --11 1111
RCSTAx
SPEN
RX9
SREN CREN ADDEN FERR OERR RX9D 0000 000x 0000 000x
TXREGx Enhanced USARTx Transmit Register
0000 0000 0000 0000
TXSTAx
CSRC
TX9
TXEN SYNC SENDB BRGH TRMT TX9D 0000 0010 0000 0010
BAUDCONx
—
RCIDL
— SCKP BRG16 —
WUE ABDEN -1-0 0-00 -1-0 0-00
SPBRGHx Enhanced USARTx Baud Rate Generator Register High Byte
0000 0000 0000 0000
SPBRGx Enhanced USARTx Baud Rate Generator Register Low Byte
0000 0000 0000 0000
Legend: x = unknown, – = unimplemented locations read as ‘0’. Shaded cells are not used for asynchronous transmission.
Note 1: Enabled only in Microcontroller mode for PIC18F8525/8621 devices.
DS39612C-page 222
 2003-2013 Microchip Technology Inc.