PIC16F87/88
When setting up a synchronous slave reception, follow
these steps:
11.4.2
USART SYNCHRONOUS SLAVE
RECEPTION
1. Enable the synchronous master serial port by
setting bits SYNC and SPEN and clearing bit
CSRC.
The operation of the Synchronous Master and Slave
modes is identical, except in the case of the SLEEP
mode. Bit SREN is a “don't care” in Slave mode.
2. If interrupts are desired, set enable bit RCIE.
3. If 9-bit reception is desired, set bit RX9.
4. To enable reception, set enable bit CREN.
If receive is enabled by setting bit CREN prior to the
SLEEPinstruction, then a word may be received during
SLEEP. On completely receiving the word, the RSR
register will transfer the data to the RCREG register
and if enable bit RCIE bit is set, the interrupt generated
will wake the chip from SLEEP. If the global interrupt is
enabled, the program will branch to the interrupt vector
(0004h).
5. Flag bit RCIF will be set when reception is com-
plete and an interrupt will be generated, if
enable bit RCIE was set.
6. Read the RCSTA register to get the ninth bit (if
enabled) and determine if any error occurred
during reception.
7. Read the 8-bit received data by reading the
RCREG register.
8. If any error occurred, clear the error by clearing
bit CREN.
9. If using interrupts, ensure that GIE and PEIE
(bits 7 and 6) of the INTCON register are set.
TABLE 11-13: REGISTERS ASSOCIATED WITH SYNCHRONOUS SLAVE RECEPTION
Value on
all other
RESETS
Value on:
POR, BOR
Address
Name
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
0Bh, 8Bh, INTCON
10Bh,18Bh
GIE
PEIE TMR0IE INTE
RBIE
TMR0IF
INTF
R0IF
0000 000x 0000 000u
0Ch
PIR1
—
ADIF
RX9
RCIF
TXIF
SSPIF CCP1IF TMR2IF TMR1IF -000 0000 -000 0000
18h
RCSTA
SPEN
SREN CREN ADDEN FERR
OERR
RX9D 0000 000x 0000 000x
1Ah
RCREG USART Receive Register
0000 0000 0000 0000
8Ch
PIE1
—
ADIE
TX9
RCIE
TXIE
SSPIE CCP1IE TMR2IE TMR1IE -000 0000 -000 0000
98h
TXSTA
CSRC
TXEN SYNC
—
BRGH
TRMT
TX9D 0000 -010 0000 -010
99h
SPBRG Baud Rate Generator Register
0000 0000 0000 0000
Legend:
x= unknown, - = unimplemented, read as ‘0’. Shaded cells are not used for synchronous slave reception.
DS30487B-page 112
Preliminary
2003 Microchip Technology Inc.
MICROCHIP [ MICROCHIP ]
