Datasheet

 2010-2012 Microchip Technology Inc. DS41412F-page 295
PIC18(L)F2X/4XK22
16.5.2.3 EUSART Synchronous Slave
Reception
The operation of the Synchronous Master and Slave
modes is identical (Section 16.5.1.6 “Synchronous
Master Reception”), with the following exceptions:
• Sleep
• CREN bit is always set, therefore the receiver is
never Idle
• SREN bit, which is a “don't care” in Slave mode
A character may be received while in Sleep mode by
setting the CREN bit prior to entering Sleep. 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 device from Sleep
and execute the next instruction. If the GIE/GIEH bit is
also set, the program will branch to the interrupt vector.
16.5.2.4 Synchronous Slave Reception
Setup:
1. Set the SYNC and SPEN bits and clear the
CSRC bit.
2. Set the RXx/DTx and TXx/CKx TRIS controls to
‘1’.
3. If using interrupts, ensure that the GIE/GIEH
and PEIE/GIEL bits of the INTCON register are
set and set the RCxIE bit.
4. If 9-bit reception is desired, set the RX9 bit.
5. Set the CREN bit to enable reception.
6. The RCxIF bit will be set when reception is
complete. An interrupt will be generated if the
RCxIE bit was set.
7. If 9-bit mode is enabled, retrieve the Most
Significant bit from the RX9D bit of the RCSTAx
register.
8. Retrieve the eight Least Significant bits from the
receive FIFO by reading the RCREGx register.
9. If an overrun error occurs, clear the error by
either clearing the CREN bit of the RCSTAx
register or by clearing the SPEN bit which resets
the EUSART.
TABLE 16-10: REGISTERS ASSOCIATED WITH SYNCHRONOUS SLAVE RECEPTION
Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
Register
on Page
BAUDCON1
ABDOVF RCIDL DTRXP CKTXP BRG16 — WUE ABDEN 279
BAUDCON2 ABDOVF RCIDL DTRXP CKTXP BRG16 — WUE ABDEN 279
INTCON GIE/GIEH PEIE/GIEL
TMR0IE INT0IE RBIE TMR0IF INT0IF RBIF 116
IPR1 — ADIP RC1IP TX1IP SSP1IP CCP1IP TMR2IP TMR1IP 128
IPR3
SSP2IP BCL2IP RC2IP TX2IP CTMUIP TMR5GIP TMR3GIP TMR1GIP 130
PIE1 — ADIE RC1IE TX1IE SSP1IE CCP1IE TMR2IE TMR1IE 124
PIE3
SSP2IE BCL2IE RC2IE TX2IE CTMUIE TMR5GIE TMR3GIE TMR1GIE 126
PIR1
— ADIF RC1IF TX1IF SSP1IF CCP1IF TMR2IF TMR1IF 119
PIR3
SSP2IF BCL2IF RC2IF TX2IF CTMUIF TMR5GIF TMR3GIF TMR1GIF 121
PMD0 UART2MD UART1MD TMR6MD TMR5MD TMR4MD TMR3MD TMR2MD TMR1MD 55
RCREG1 EUSART1 Receive Register
—
RCSTA1 SPEN RX9 SREN CREN ADDEN FERR OERR RX9D 278
RCREG2 EUSART2 Receive Register
—
RCSTA2 SPEN RX9 SREN CREN ADDEN FERR OERR RX9D 278
SPBRG1 EUSART1 Baud Rate Generator, Low Byte
—
SPBRGH1 EUSART1 Baud Rate Generator, High Byte
—
SPBRG2 EUSART2 Baud Rate Generator, Low Byte
—
SPBRGH2 EUSART2 Baud Rate Generator, High Byte
—
TXSTA1 CSRC TX9 TXEN SYNC SENDB BRGH TRMT TX9D 277
TXSTA2 CSRC TX9 TXEN SYNC SENDB BRGH TRMT TX9D 277
Legend: — = unimplemented locations, read as ‘0’. Shaded bits are not used for synchronous slave reception.