PIC18F1220_07 Datasheet, PDF (155/308 Pages) Microchip Technology – 18/20/28-Pin High-Performance, Enhanced Flash Microcontrollers with 10-bit A/D and nanoWatt Technology

PIC18F1220/1320
16.5.2 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 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 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
Value on
POR, BOR
Value on
all other
Resets
INTCON GIE/GIEH PEIE/GIEL TMR0IE INT0IE RBIE TMR0IF INT0IF RBIF 0000 000x 0000 000u
PIR1
—
ADIF
RCIF TXIF
— CCP1IF TMR2IF TMR1IF -000 -000 -000 -000
PIE1
—
ADIE
RCIE TXIE
— CCP1IE TMR2IE TMR1IE -000 -000 -000 -000
IPR1
—
ADIP
RCIP TXIP
— CCP1IP TMR2IP TMR1IP -111 -111 -111 -111
RCSTA
SPEN
RX9
SREN CREN ADDEN FERR OERR RX9D 0000 000x 0000 000x
RCREG EUSART Receive Register
0000 0000 0000 0000
TXSTA
CSRC
TX9
TXEN SYNC SENDB BRGH TRMT TX9D 0000 0010 0000 0010
BAUDCTL
—
RCIDL
—
SCKP BRG16
—
WUE ABDEN -1-1 0-00 -1-1 0-00
SPBRGH Baud Rate Generator Register High Byte
0000 0000 0000 0000
SPBRG Baud Rate Generator Register Low Byte
0000 0000 0000 0000
Legend: x = unknown, – = unimplemented, read as ‘0’. Shaded cells are not used for synchronous slave reception.
© 2007 Microchip Technology Inc.
DS39605F-page 153