Datasheet

 2000-2013 Microchip Technology Inc. DS30569C-page 69
PIC16F870/871
When setting up an Asynchronous Reception, follow
these steps:
1. Initialize the SPBRG register for the appropriate
baud rate. If a high speed baud rate is desired,
set bit BRGH (Section 9.1).
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 is 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.
10. If using interrupts, ensure that GIE and PEIE
(bits 7 and 6) of the INTCON register are set.
TABLE 9-6: 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
0Bh, 8Bh,
10Bh,18Bh
INTCON GIE PEIE
T0IE INTE RBIE T0IF INTF R0IF 0000 000x 0000 000u
0Ch PIR1
PSPIF
(1)
ADIF RCIF TXIF — CCP1IF TMR2IF TMR1IF
-000 0000 -000 0000
18h RCSTA SPEN RX9
SREN CREN — FERR OERR RX9D
0000 -00x 0000 -00x
1Ah RCREG USART Receive Register
0000 0000 0000 0000
8Ch PIE1
PSPIE
(1)
ADIE RCIE TXIE — CCP1IE TMR2IE TMR1IE
0000 -000 0000 -000
98h TXSTA
CSRC TX9 TXEN SYNC —BRGHTRMT TX9D
0000 -010 0000 -010
99h SPBRG Baud Rate Generator Register
0000 0000 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 PIC16F870; always maintain these bits clear.