PIC16F627A_05 Datasheet, PDF (81/180 Pages) Microchip Technology – Flash-Based, 8-Bit CMOS Microcontrollers with nanoWatt Technology

PIC16F627A/628A/648A
FIGURE 12-3:
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: This 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
— CCP1IF TMR2IF TMR1IF
RCSTA SPEN RX9 SREN CREN ADEN FERR OERR RX9D
TXREG USART Transmit Data Register
PIE1
EEIE CMIE RCIE TXIE
— CCP1IE TMR2IE TMR1IE
TXSTA CSRC TX9 TXEN SYNC — BRGH TRMT TX9D
SPBRG Baud Rate Generator Register
x = unknown, - = unimplemented locations read as ‘0’.
Shaded cells are not used for Asynchronous Transmission.
0000 -000
0000 000x
0000 0000
0000 -000
0000 -010
0000 0000
0000 -000
0000 000x
0000 0000
0000 -000
0000 -010
0000 0000
© 2005 Microchip Technology Inc.
DS40044D-page 79