Microchip Technology ARD00385 Data Sheet
PIC18F87K90 FAMILY
DS39957D-page 372
2009-2011 Microchip Technology Inc.
22.4.2
EUSART SYNCHRONOUS SLAVE
RECEPTION
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
RCREGx register. If the RCxIE 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.
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
RCREGx register. If the RCxIE 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.
1.
Enable the synchronous master serial port by
setting bits, SYNC and SPEN, and clearing bit,
CSRC.
setting bits, SYNC and SPEN, and clearing bit,
CSRC.
2.
If interrupts are desired, set enable bit, RCxIE.
3.
If 9-bit reception is desired, set bit, RX9.
4.
To enable reception, set enable bit, CREN.
5.
Flag bit, RCxIF, will be set when reception is
complete. An interrupt will be generated if
enable bit, RCxIE, was set.
complete. An interrupt will be generated if
enable bit, RCxIE, was set.
6.
Read the RCSTAx register to get the 9th bit (if
enabled) and determine if any error occurred
during reception.
enabled) and determine if any error occurred
during reception.
7.
Read the 8-bit received data by reading the
RCREGx register.
RCREGx register.
8.
If any error occurred, clear the error by clearing
bit, CREN.
bit, CREN.
9.
If using interrupts, ensure that the GIE and PEIE
bits in the INTCON register (INTCON<7:6>) are
set.
bits in the INTCON register (INTCON<7:6>) are
set.
TABLE 22-10: 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
PIR1
—
ADIF
RC1IF
TX1IF
SSP1IF
TMR1GIF TMR2IF
TMR1IF
PIE1
—
ADIE
RC1IE
TX1IE
SSP1IE
TMR1GIE TMR2IE
TMR1IE
IPR1
—
ADIP
RC1IP
TX1IP
SSP1IP
TMR1GIP TMR2IP
TMR1IP
PIR3
TMR5GIF
LCDIF
RC2IF
TX2IF
CTMUIF
CCP2IF
CCP1IF
RTCCIF
PIE3
TMR5GIE
LCDIE
RC2IE
TX2IE
CTMUIE
CCP2IE
CCP1IE
RTCCIE
IPR3
TMR5GIP
LCDIP
RC2IP
TX2IP
CTMUIP
CCP2IP
CCP1IP
RTCCIP
RCSTA1
SPEN
RX9
SREN
CREN
ADDEN
FERR
OERR
RX9D
RCREG1
EUSART1 Receive Register
TXSTA1
CSRC
TX9
TXEN
SYNC
SENDB
BRGH
TRMT
TX9D
BAUDCON1 ABDOVF
RCIDL
RXDTP
TXCKP
BRG16
—
WUE
ABDEN
SPBRGH1
EUSART1 Baud Rate Generator Register High Byte
SPBRG1
EUSART1 Baud Rate Generator Register Low Byte
RCSTA2
SPEN
RX9
SREN
CREN
ADDEN
FERR
OERR
RX9D
RCREG2
EUSART2 Receive Register
TXSTA2
CSRC
TX9
TXEN
SYNC
SENDB
BRGH
TRMT
TX9D
BAUDCON2 ABDOVF
RCIDL
RXDTP
TXCKP
BRG16
—
WUE
ABDEN
SPBRGH2
EUSART2 Baud Rate Generator Register High Byte
SPBRG2
EUSART2 Baud Rate Generator Register Low Byte
Legend:
— = unimplemented, read as ‘0’. Shaded cells are not used for synchronous slave reception.