Datasheet
PIC18F2331/2431/4331/4431
DS39616D-page 238 2010 Microchip Technology Inc.
20.5.2 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 inter-
rupt generated will wake the chip from 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 9-bit reception is desired, set bit, RX9.
4. To enable reception, set enable bit, CREN.
5. Flag bit, RCIF, will be set when reception is
complete. An interrupt will be generated if
enable bit, RCIE, was set.
6. Read the RCSTA register to get the 9th 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 the GIE and PEIE
bits in the INTCON register (INTCON<7:6>) are
set.
TABLE 20-10: 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 54
PIR1 — ADIF RCIF TXIF SSPIF CCP1IF TMR2IF TMR1IF 57
PIE1
— ADIE RCIE TXIE SSPIE CCP1IE TMR2IE TMR1IE 57
IPR1 — ADIP RCIP TXIP SSPIP CCP1IP TMR2IP TMR1IP 57
RCSTA SPEN RX9 SREN CREN ADDEN FERR OERR RX9D 56
RCREG EUSART Receive Register 56
TXSTA CSRC
TX9 TXEN SYNC SENDB BRGH TRMT TX9D 56
BAUDCON — RCIDL — SCKP BRG16 — WUE ABDEN 56
SPBRGH EUSART Baud Rate Generator Register High Byte 56
SPBRG EUSART Baud Rate Generator Register Low Byte 56
Legend: — = unimplemented, read as ‘0’. Shaded cells are not used for synchronous slave reception.