PIC18F2585_07 Datasheet, PDF (248/482 Pages) Microchip Technology – Enhanced Flash Microcontrollers with ECAN Technology, 10-Bit A/D and nanoWatt Technology

PIC18F2585/2680/4585/4680
18.4.2 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 inter-
rupt 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 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 18-10: 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
49
PIR1
PSPIF⁽¹⁾ ADIF
RCIF
TXIF
SSPIF CCP1IF TMR2IF TMR1IF
52
PIE1
PSPIE⁽¹⁾ ADIE
RCIE
TXIE
SSPIE CCP1IE TMR2IE TMR1IE
52
IPR1
PSPIP⁽¹⁾ ADIP
RCIP
TXIP
SSPIP CCP1IP TMR2IP TMR1IP
52
RCSTA
SPEN
RX9
SREN CREN ADDEN FERR OERR RX9D
51
RCREG
EUSART Receive Register
51
TXSTA
CSRC
TX9
TXEN SYNC SENDB BRGH TRMT TX9D
51
BAUDCON ABDOVF RCIDL
—
SCKP BRG16
—
WUE ABDEN
51
SPBRGH EUSART Baud Rate Generator Register High Byte
51
SPBRG
EUSART Baud Rate Generator Register Low Byte
51
Legend: — = unimplemented, read as ‘0’. Shaded cells are not used for synchronous slave reception.
Note 1: Reserved in PIC18F2X8X devices; always maintain these bits clear.
DS39625C-page 246
Preliminary
© 2007 Microchip Technology Inc.