PIC18F2450/4450
To set up a Synchronous Slave Reception:
15.4.2
EUSART 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 Sleep or any
Idle mode and bit SREN, which 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 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.
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 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 the GIE and PEIE
bits in the INTCON register (INTCON<7:6>) are
set.
TABLE 15-10: REGISTERS ASSOCIATED WITH SYNCHRONOUS SLAVE RECEPTION
Reset
Values
on page
Name
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
INTCON
PIR1
GIE/GIEH PEIE/GIEL TMR0IE
INT0IE
TXIF
RBIE
—
TMR0IF
CCP1IF
INT0IF
RBIF
49
51
51
51
51
50
51
51
50
50
—
—
ADIF
ADIE
ADIP
RX9
RCIF
RCIE
RCIP
SREN
TMR2IF TMR1IF
PIE1
TXIE
—
CCP1IE TMR2IE TMR1IE
CCP1IP TMR2IP TMR1IP
IPR1
—
TXIP
—
RCSTA
RCREG
TXSTA
SPEN
CREN
ADDEN
FERR
OERR
RX9D
EUSART Receive Register
CSRC
TX9
TXEN
—
SYNC
SCKP
SENDB
BRG16
BRGH
—
TRMT
WUE
TX9D
BAUDCON ABDOVF
RCIDL
ABDEN
SPBRGH
SPBRG
EUSART Baud Rate Generator Register High Byte
EUSART Baud Rate Generator Register Low Byte
Legend: — = unimplemented, read as ‘0’. Shaded cells are not used for synchronous slave reception.
DS39760A-page 172
Advance Information
© 2006 Microchip Technology Inc.