PIC16F628-20P Datasheet, PDF (78/170 Pages) Microchip Technology – FLASH-Based 8-Bit CMOS Microcontroller

PIC16F62X
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 1: 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
PIR1
EEIF CMIF RCIF TXIF
—
18h
RCSTA SPEN RX9 SREN CREN ADEN
19h
TXREG USART Transmit Register
8Ch
PIE1
EEIE CMIE RCIE TXIE
—
98h
TXSTA CSRC TX9 TXEN SYNC —
99h
SPBRG Baud Rate Generator Register
Legend: x = unknown, - = unimplemented locations read as '0'.
Shaded cells are not used for Asynchronous Transmission.
CCP1IF TMR2IF TMR1IF
FERR OERR RX9D
CCP1IE TMR2IE TMR1IE
BRGH TRMT TX9D
0000 -000
0000 -00x
0000 0000
0000 -000
0000 -010
0000 0000
0000 -000
0000 -00x
0000 0000
0000 -000
0000 -010
0000 0000
DS40300C-page 76
Preliminary
 2003 Microchip Technology Inc.