SH7706 Datasheet, PDF (463/749 Pages) Renesas Technology Corp – Renesas 32-Bit RISC Microcomputer SuperH™ RISC engine Family/SH7700 Series

Section 14 Serial Communication Interface (SCI)
In receiving, the SCI operates as follows:
1. The SCI synchronizes with serial clock input or output and initializes internally.
2. Receive data is stored into the SCRSR in order from the LSB to the MSB. After receiving the
data, the SCI checks that RDRF is 0 so that receive data can be loaded from the SCRSR into
the SCRDR. If this check is passed, the SCI sets RDRF to 1 and stores the received data in the
SCRDR. If the check is not passed (receive error), the SCI operates as indicated in table 14.11.
This state prevents further transmission or reception. While receiving, the RDRF bit is not set
to 1. Be sure to clear the error flag.
3. After setting RDRF to 1, if the RIE is set to 1 in the SCSCR, the SCI requests a receive-data-
full interrupt (RXI). If the ORER bit is set to 1 and the RIE in the SCSCR is also set to 1, the
SCI requests a receive-error interrupt (ERI).
Figure 14.22 shows an example of the SCI receive operation.
Transfer direction
Synchronization
clock
Serial
data
Bit 7 Bit 0
RDRF
Bit 7 Bit 0 Bit 1
Bit 6 Bit 7
ORER
RXI interrupt
request
generated
Reads data with
the RXI interrupt
processing routine
and clears RDRF
bit to 0
RXI interrupt
request
generated
ERI interrupt
request generated
by overrun error
1 frame
Figure 14.22 Example of SCI Receive Operation
Rev. 5.00 May 29, 2006 page 415 of 698
REJ09B0146-0500