PIC16LC63A-04 Datasheet, PDF (69/184 Pages) Microchip Technology – 8-Bit CMOS Microcontrollers with A/D Converter

PIC16C63A/65B/73B/74B
Steps to follow when setting up an Asynchronous
Transmission:
1. Initialize the SPBRG register for the appropriate
baud rate. If a high speed baud rate is desired,
set bit BRGH. (Section 11.1)
2. Enable the asynchronous serial port by clearing
bit SYNC and setting bit SPEN.
3. If interrupts are desired, set interrupt enable bits
TXIE (PIE1<4>), PEIE (INTCON<6>), and GIE
(INTCON<7>), as required.
4. If 9-bit transmission is desired, then set transmit
bit TX9.
5. Enable the transmission by setting bit TXEN,
which will also set flag bit TXIF.
6. If 9-bit transmission is selected, the ninth bit
should be loaded in bit TX9D.
7. Load data to the TXREG register (starts trans-
mission).
FIGURE 11-2:
ASYNCHRONOUS MASTER TRANSMISSION
Write to TXREG
BRG output
(shift clock)
RC6/TX/CK (pin)
TXIF bit
(Transmit buffer
reg. empty flag)
Word 1
START Bit
Bit 0
Bit 1
Word 1
Bit 7/8 _{STOP Bit}
TRMT bit
(Transmit shift
reg. empty flag)
Word 1
Transmit Shift Reg
FIGURE 11-3:
Write to TXREG
BRG output
(shift clock)
RC6/TX/CK (pin)
TXIF bit
(interrupt reg. flag)
ASYNCHRONOUS MASTER TRANSMISSION (BACK TO BACK)
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
(Transmit shift
reg. empty flag)
Word 1
Transmit Shift Reg.
Word 2
Transmit Shift Reg.
Note: This timing diagram shows two consecutive transmissions.
TABLE 11-3: 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
Value on
all other
RESETS
0Bh,8Bh INTCON GIE
PEIE T0IE INTE RBIE T0IF
INTF
RBIF 0000 000x
0Ch
PIR1
PSPIF⁽¹⁾ ADIF⁽²⁾ RCIF TXIF SSPIF CCP1IF TMR2IF TMR1IF 0000 0000
18h
RCSTA SPEN RX9 SREN CREN — FERR OERR RX9D 0000 -00x
19h
TXREG USART Transmit Register
0000 0000
8Ch
PIE1
PSPIE⁽¹⁾ ADIE⁽²⁾ RCIE TXIE SSPIE CCP1IE TMR2IE TMR1IE 0000 0000
98h
TXSTA CSRC TX9 TXEN SYNC — BRGH TRMT TX9D 0000 -010
99h
SPBRG Baud Rate Generator Register
0000 0000
Legend: u = unchanged, x = unknown, - = unimplemented locations read as '0'.
Shaded cells are not used for asynchronous transmission.
Note 1: Bits PSPIE and PSPIF are reserved on the PIC16C63A/73B; always maintain these bits clear.
2: Bits ADIE and ADIF are reserved on the PIC16C63A/65B; always maintain these bits clear.
0000 000u
0000 0000
0000 -00x
0000 0000
0000 0000
0000 -010
0000 0000
 2000 Microchip Technology Inc.
DS30605C-page 69