PIC18F97J60_11 Datasheet, PDF (335/492 Pages) Microchip Technology – 64/80/100-Pin, High-Performance, 1-Mbit Flash Microcontrollers with Ethernet

PIC18F97J60 FAMILY
21.3.2
EUSARTx SYNCHRONOUS
MASTER RECEPTION
Once Synchronous mode is selected, reception is
enabled by setting either the Single Receive Enable bit,
SREN (RCSTAx<5>), or the Continuous Receive
Enable bit, CREN (RCSTAx<4>). Data is sampled on
the RXx pin on the falling edge of the clock.
If enable bit, SREN, is set, only a single word is
received. If enable bit, CREN, is set, the reception is
continuous until CREN is cleared. If both bits are set,
then CREN takes precedence.
To set up a Synchronous Master Reception:
1. Initialize the SPBRGHx:SPBRGx registers for the
appropriate baud rate. Set or clear the BRG16
bit, as required, to achieve the desired baud rate.
2. Enable the synchronous master serial port by
setting bits, SYNC, SPEN and CSRC.
3. Ensure bits, CREN and SREN, are clear.
4. If the signal from the CKx pin is to be inverted,
set the TXCKP bit. If the signal from the DTx pin
is to be inverted, set the RXDTP bit.
5. If interrupts are desired, set enable bit, RCxIE.
6. If 9-bit reception is desired, set bit, RX9.
7. If a single reception is required, set bit, SREN.
For continuous reception, set bit, CREN.
8. Interrupt flag bit, RCxIF, will be set when recep-
tion is complete and an interrupt will be generated
if the enable bit, RCxIE, was set.
9. Read the RCSTAx register to get the 9th bit (if
enabled) and determine if any error occurred
during reception.
10. Read the 8-bit received data by reading the
RCREGx register.
11. If any error occurred, clear the error by clearing
bit, CREN.
12. If using interrupts, ensure that the GIE and PEIE
bits in the INTCON register (INTCON<7:6>) are
set.
FIGURE 21-13: SYNCHRONOUS RECEPTION (MASTER MODE, SREN)
Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4
RC7/RX1/DT1
pin
bit 0
bit 1
bit 2
bit 3
bit 4
bit 5
bit 6
bit 7
RC6/TX1/CK1 pin
(TXCKP = 0)
RC6/TX1/CK1 pin
(TXCKP = 1)
Write to
SREN bit
SREN bit
CREN bit ‘0’
‘0’
RC1IF bit
(Interrupt)
Read
RCREG1
Note: Timing diagram demonstrates Sync Master mode with bit SREN = 1 and bit BRGH = 0. This example is equally applicable to EUSART2
(RG1/TX2/CK2 and RG2/RX2/DT2).
 2011 Microchip Technology Inc.
DS39762F-page 335