Hitachi SH7032 Hardware Manual page 435

Figure 13.18 Sample Flowchart for Serial Receiving (cont)
Receive direction
Serial
clock
Serial
Bit 7
data
RDRF
ORER
RXI request
In receiving, the SCI operates as follows:
1. The SCI synchronizes with serial clock input or output and initializes internally.
2. Receive data is shifted into RSR 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 RSR into RDR. If this
check passes, the SCI sets RDRF to 1 and stores the received data in RDR. If the check does
not pass (receive error), the SCI operates as indicated in table 13.8. When the error flag is set
400
No
Overrun error handling
Clear ORER bit in SSR to 0
Bit 0 Bit 7
RXI interrupt handler
reads data in RDR
and clears RDRF to 0
1 frame
Figure 13.19 Example of SCI Receive Operation
Error handling
ORER = 1?
Yes
End
Bit 0 Bit 1
RXI request
Bit 6 Bit 7
Overrun
error, ERI
request