
PIC16C745/765
DS41124C-page 84
Preliminary
2000 Microchip Technology Inc.
Steps to follow when setting up an Asynchronous
Reception:
1.
Initialize the SPBRG register for the appropriate
baud rate. If a high speed baud rate is desired,
2.
Enable the asynchronous serial port by clearing
bit SYNC, and setting bit SPEN.
3.
If interrupts are desired, then set enable bit
RCIE.
4.
If 9-bit reception is desired, then set bit RX9.
5.
Enable the reception by setting bit CREN.
6.
Flag bit RCIF will be set when reception is com-
plete and an interrupt will be generated if enable
bit RCIE was set.
7.
Read the RCSTA register to get the ninth bit (if
enabled) and determine if any error occurred
during reception.
8.
Read the 8-bit received data by reading the
RCREG register.
9.
If any error occurred, clear the error by clearing
enable bit CREN.
TABLE 11-7:
REGISTERS ASSOCIATED WITH ASYNCHRONOUS RECEPTION
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
0Ch
PIR1
PSPIF(1)
ADIF
RCIF
TXIF
USBIF
CCP1IF
TMR2IF
TMR1IF
0000 0000
18h
RCSTA
SPEN
RX9
SREN
CREN
—
FERR
OERR
RX9D
0000 -00x
1Ah
RCREG USART Receive Register
0000 0000
8Ch
PIE1
PSPIE(1)
ADIE
RCIE
TXIE
USBIE
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: x = unknown, - = unimplemented locations read as '0'. Shaded cells are not used for asynchronous reception.
Note 1: Bits PSPIE and PSPIF are reserved on the PIC16C745; always maintain these bits clear.
745cov.book Page 84 Wednesday, August 2, 2000 8:24 AM