PIC17C7XX Datasheet, PDF (122/328 Pages) Microchip Technology – High-Performance 8-Bit CMOS EPROM Microcontrollers with 10-bit A/D

PIC17C7XX
FIGURE 14-5: ASYNCHRONOUS MASTER TRANSMISSION
Write to TXREG
BRG output
(shift clock)
TX
(TX/CK pin)
TXIF bit
Word 1
Start Bit
Bit 0
Bit 1
Word 1
TRMT bit
Word 1
Transmit Shift Reg
Bit 7/8 _{Stop Bit}
FIGURE 14-6: ASYNCHRONOUS MASTER TRANSMISSION (BACK TO BACK)
Write to TXREG
BRG output
(shift clock)
TX
(TX/CK pin)
TXIF bit
Word 1 Word 2
Start Bit
Bit 0
Bit 1
Word 1
Bit 7/8
Stop Bit
Start Bit
Word 2
Bit 0
TRMT bit
Word 1
Transmit Shift Reg.
Word 2
Transmit Shift Reg.
Note: This timing diagram shows two consecutive transmissions.
TABLE 14-6: 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,
BOR
MCLR, WDT
16h, Bank 1 PIR1
RBIF TMR3IF TMR2IF TMR1IF CA2IF CA1IF TX1IF
RC1IF x000 0010
17h, Bank 1 PIE1
RBIE TMR3IE TMR2IE TMR1IE CA2IE CA1IE TX1IE
RC1IE 0000 0000
13h, Bank 0 RCSTA1
SPEN RX9 SREN CREN — FERR OERR
RX9D 0000 -00x
16h, Bank 0 TXREG1 Serial port transmit register (USART1)
xxxx xxxx
15h, Bank 0 TXSTA1
CSRC TX9 TXEN SYNC —
—
TRMT
TX9D 0000 --1x
17h, Bank 0 SPBRG1 Baud rate generator register (USART1)
0000 0000
10h, Bank 4 PIR2
SSPIF BCLIF ADIF
— CA4IF CA3IF TX2IF
RC2IF 000- 0010
11h, Bank 4 PIE2
SSPIE BCLIE ADIE
— CA4IE CA3IE TX2IE
RC2IE 000- 0000
13h, Bank 4 RCSTA2
SPEN RX9 SREN CREN — FERR OERR
RX9D 0000 -00x
16h, Bank 4 TXREG2 Serial port transmit register (USART2)
xxxx xxxx
15h, Bank 4 TXSTA2
CSRC TX9 TXEN SYNC —
—
TRMT
TX9D 0000 --1x
17h, Bank 4 SPBRG2 Baud rate generator register (USART2)
0000 0000
Legend: x = unknown, u = unchanged, - = unimplemented read as a '0', shaded cells are not used for asynchronous
transmission.
u000 0010
0000 0000
0000 -00u
uuuu uuuu
0000 --1u
0000 0000
000- 0010
000- 0000
0000 -00u
uuuu uuuu
0000 --1u
0000 0000
DS30289A-page 122
© 1998 Microchip Technology Inc.