Datasheet

 2011-2013 Microchip Technology Inc. DS40001453E-page 313
PIC16(L)F1847
26.4.2 SYNCHRONOUS SLAVE MODE
The following bits are used to configure the EUSART
for Synchronous slave operation:
• SYNC = 1
• CSRC = 0
• SREN = 0 (for transmit); SREN = 1 (for receive)
• CREN = 0 (for transmit); CREN = 1 (for receive)
• SPEN = 1
Setting the SYNC bit of the TXSTA register configures
the device for synchronous operation. Clearing the
CSRC bit of the TXSTA register configures the device as
a slave. Clearing the SREN and CREN bits of the RCSTA
register ensures that the device is in the Transmit mode,
otherwise the device will be configured to receive. Setting
the SPEN bit of the RCSTA register enables the
EUSART.
26.4.2.1 EUSART Synchronous Slave
Transmit
The operation of the Synchronous Master and Slave
modes are identical (see Section 26.4.1.3
“Synchronous Master Transmission”), except in the
case of the Sleep mode.
If two words are written to the TXREG and then the
SLEEP instruction is executed, the following will occur:
1. The first character will immediately transfer to
the TSR register and transmit.
2. The second word will remain in TXREG register.
3. The TXIF bit will not be set.
4. After the first character has been shifted out of
TSR, the TXREG register will transfer the second
character to the TSR and the TXIF bit will now be
set.
5. If the PEIE and TXIE bits are set, the interrupt
will wake the device from Sleep and execute the
next instruction. If the GIE bit is also set, the
program will call the Interrupt Service Routine.
26.4.2.2 Synchronous Slave Transmission
Setup:
1. Set the SYNC and SPEN bits and clear the
CSRC bit.
2. Clear the ANSEL bit for the CK pin (if applicable).
3. Clear the CREN and SREN bits.
4. If interrupts are desired, set the TXIE bit of the
PIE1 register and the GIE and PEIE bits of the
INTCON register.
5. If 9-bit transmission is desired, set the TX9 bit.
6. Enable transmission by setting the TXEN bit.
7. If 9-bit transmission is selected, insert the Most
Significant bit into the TX9D bit.
8. Start transmission by writing the Least
Significant eight bits to the TXREG register.
TABLE 26-9: SUMMARY OF REGISTERS ASSOCIATED WITH SYNCHRONOUS SLAVE
TRANSMISSION
Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
Register
on Page
APFCON0 RXDTSEL SDO1SEL SS1SEL P2BSEL CCP2SEL P1DSEL P1CSEL CCP1SEL 118
APFCON1
— — — — — — — TXCKSEL 118
BAUDCON
ABDOVF RCIDL —SCKPBRG16 — WUE ABDEN
298
INTCON GIE PEIE
TMR0IE INTE IOCE TMR0IF INTF IOCF
88
PIE1
TMR1GIE ADIE RCIE TXIE SSP1IE CCP1IE TMR2IE TMR1IE
89
PIR1
TMR1GIF ADIF RCIF TXIF SSP1IF CCP1IF TMR2IF TMR1IF
93
RCSTA SPEN
RX9 SREN CREN ADDEN FERR OERR RX9D
297
TRISB TRISB7 TRISB6
TRISB5 TRISB4 TRISB3 TRISB2 TRISB1 TRISB0 126
TXREG EUSART Transmit Data Register
289*
TXSTA CSRC TX9 TXEN SYNC SENDB
BRGH TRMT TX9D
296
Legend: — = unimplemented location, read as ‘0’. Shaded cells are not used for Synchronous Slave Transmission.
* Page provides register information.