Datasheet
PIC18F1230/1330
DS39758D-page 168 2009 Microchip Technology Inc.
15.4.2 EUSART SYNCHRONOUS SLAVE
RECEPTION
The operation of the Synchronous Master and Slave
modes is identical, except in the case of Sleep, or any
Idle mode and bit SREN, which is a “don’t care” in
Slave mode.
If receive is enabled by setting the CREN bit prior to
entering Sleep or any Idle mode, then a word may be
received while in this low-power mode. Once the word
is received, the RSR register will transfer the data to the
RCREG register; if the RCIE enable bit is set, the
interrupt generated will wake the chip from the low-
power mode. If the global interrupt is enabled, the
program will branch to the interrupt vector.
To set up a Synchronous Slave Reception:
1. Enable the synchronous master serial port by
setting bits, SYNC and SPEN, and clearing bit,
CSRC.
2. If interrupts are desired, set enable bit, RCIE.
3. If the signal from the CK pin is to be inverted, set
the TXCKP bit.
4. If 9-bit reception is desired, set bit, RX9.
5. To enable reception, set enable bit, CREN.
6. Flag bit, RCIF, will be set when reception is
complete. An interrupt will be generated if
enable bit, RCIE, was set.
7. Read the RCSTA register to get the 9th 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
bit, CREN.
10. If using interrupts, ensure that the GIE and PEIE
bits in the INTCON register (INTCON<7:6>) are
set.
TABLE 15-10: REGISTERS ASSOCIATED WITH SYNCHRONOUS SLAVE RECEPTION
Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
Reset
Values
on Page:
INTCON GIE/GIEH PEIE/GIEL TMR0IE INT0IE RBIE TMR0IF INT0IF RBIF 47
PIR1
— ADIF RCIF TXIF CMP2IF CMP1IF CMP0IF TMR1IF 49
PIE1 — ADIE RCIE TXIE CMP2IE CMP1IE CMP0IE TMR1IE 49
IPR1 — ADIP RCIP TXIP CMP2IP CMP1IP CMP0IP TMR1IP 49
RCSTA SPEN RX9 SREN CREN
ADDEN FERR OERR RX9D 48
RCREG EUSART Receive Register 48
TXSTA CSRC TX9 TXEN SYNC SENDB BRGH TRMT TX9D 48
BAUDCON
ABDOVF RCIDL RXDTP TXCKP BRG16 — WUE ABDEN 48
SPBRGH EUSART Baud Rate Generator Register High Byte 48
SPBRG EUSART Baud Rate Generator Register Low Byte 48
Legend: — = unimplemented, read as ‘0’. Shaded cells are not used for synchronous slave reception.