PIC16F627A Datasheet, PDF (80/168 Pages) Microchip Technology – FLASH-Based 8-Bit CMOS Microcontrollers

PIC16F627A/628A/648A
FIGURE 12-7:
Write to TXREG
BRG output
(shift clock)
RB2/TX/CK (pin)
TXIF bit
(interrupt reg. flag)
ASYNCHRONOUS TRANSMISSION (BACK TO BACK)
Word 1
Word 2
START Bit Bit 0
Bit 1
WORD 1
Bit 7/8
STOP Bit ^{START Bit}
Bit 0
WORD 2
TRMT bit
(Transmit shift
reg. empty flag)
WORD 1
Transmit Shift Reg.
Note: Th.is timing diagram shows two consecutive transmissions.
WORD 2
Transmit Shift Reg.
TABLE 12-6: REGISTERS ASSOCIATED WITH ASYNCHRONOUS TRANSMISSION
Address Name
Bit 7
Bit 6 Bit 5 Bit 4 Bit 3 Bit 2
Bit 1
Bit 0
Value on
POR
Value on
all other
RESETS
0Ch
18h
19h
8Ch
98h
99h
Legend:
PIR1
EEIF CMIF RCIF TXIF
—
RCSTA SPEN RX9 SREN CREN ADEN
TXREG USART Transmit data register
PIE1
EEIE CMIE RCIE TXIE
—
TXSTA CSRC TX9 TXEN SYNC —
SPBRG Baud Rate Generator Register
x = unknown, - = unimplemented locations read as '0'.
Shaded cells are not used for Asynchronous Transmission.
CCP1IF
FERR
CCP1IE
BRGH
TMR2IF
OERR
TMR2IE
TRMT
TMR1IF
RX9D
TMR1IE
TX9D
0000 -000
0000 000x
0000 0000
0000 -000
0000 -010
0000 0000
0000 -000
0000 000x
0000 0000
0000 -000
0000 -010
0000 0000
DS40044A-page 78
Preliminary
 2002 Microchip Technology Inc.