Figure 19.17 Example Of Scif Receive Operation - Renesas HD6417641 Hardware Manual

Section 19 Serial Communication Interface with FIFO (SCIF)
In serial reception, the SCIF operates as described below.
1. The SCIF synchronizes with serial clock input or output and starts the reception.
2. Receive data is shifted into SCRSR in order from the LSB to the MSB. After receiving the
data, the SCIF checks the receive data can be loaded from SCRSR into SCFRDR or not. If this
check is passed, the SCIF stores the received data in SCFRDR. If the check is not passed
(overrun error is detected), further reception is prevented.
3. After setting RDF to 1, if the receive-data-full interrupt enable bit (RIE) is set to 1 in SCSCR,
the SCIF requests a receive-data-full interrupt (RXI). If the ORER bit is set to 1 and the
receive-data-full interrupt enable bit (RIE) or the receive error interrupt enable bit (REIE) in
SCSCR is also set to 1, the SCIF requests a break interrupt (BRI).
Figure 19.17 shows an example of SCIF receive operation.
Synchronization
clock
Serial data
RDF
ORER
Rev. 4.00 Sep. 14, 2005 Page 740 of 982
REJ09B0023-0400
LSB
Bit 7 Bit 0
RXI Data read from
interrupt SCFRDR and
request RDF flag cleared
to 0 by RXI
interrupt handler
One frame

Figure 19.17 Example of SCIF Receive Operation

MSB
Bit 7 Bit 0 Bit 1
RXI
interrupt
request
Bit 6 Bit 7
BRI interrupt request
by overrun error