PIC18F-LF1XK50 Datasheet, PDF (204/420 Pages) Microchip Technology – 20-Pin USB Flash Microcontrollers

PIC18F/LF1XK50
16.4.1.9 Receiving 9-bit Characters
The EUSART supports 9-bit character reception. When
the RX9 bit of the RCSTA register is set the EUSART
will shift 9-bits into the RSR for each character
received. The RX9D bit of the RCSTA register is the
ninth, and Most Significant, data bit of the top unread
character in the receive FIFO. When reading 9-bit data
from the receive FIFO buffer, the RX9D data bit must
be read before reading the 8 Least Significant bits from
the RCREG.
16.4.1.10 Synchronous Master Reception
Set-up:
1. Initialize the SPBRGH, SPBRG register pair for
the appropriate baud rate. Set or clear the
BRGH and BRG16 bits, as required, to achieve
the desired baud rate.
2. Enable the synchronous master serial port by
setting bits SYNC, SPEN and CSRC. Disable
RX/DT and TX/CK output drivers by setting the
corresponding TRIS bits.
3. Ensure bits CREN and SREN are clear.
4. If using interrupts, set the GIE and PEIE bits of
the INTCON register and set RCIE.
5. If 9-bit reception is desired, set bit RX9.
6. Start reception by setting the SREN bit or for
continuous reception, set the CREN bit.
7. Interrupt flag bit RCIF will be set when reception
of a character is complete. An interrupt will be
generated if the enable bit RCIE was set.
8. Read the RCSTA register to get the ninth bit (if
enabled) and determine if any error occurred
during reception.
9. Read the 8-bit received data by reading the
RCREG register.
10. If an overrun error occurs, clear the error by
either clearing the CREN bit of the RCSTA
register or by clearing the SPEN bit which resets
the EUSART.
FIGURE 16-12: SYNCHRONOUS RECEPTION (MASTER MODE, SREN)
RX/DT
pin
TX/CK pin
(SCKP = 0)
bit 0
bit 1
bit 2
bit 3
bit 4
bit 5
bit 6
bit 7
TX/CK pin
(SCKP = 1)
Write to
bit SREN
SREN bit
CREN bit ^{‘0’}
‘0’
RCIF bit
(Interrupt)
Read
RXREG
Note:
Timing diagram demonstrates Sync Master mode with bit SREN = 1 and bit BRGH = 0.
DS41350E-page 204
Preliminary
 2010 Microchip Technology Inc.