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Receiving
Figure 10-18 shows an example of a flowchart for data reception. This procedure should be
followed for data reception after initializing SCI3.
Start
Read bit OER
1
1. Read bit OER in the serial status register
(SSR) to determine if there is an error.
If an overrun error has occurred, execute
overrun error processing.
in SSR
Yes
OER = 1?
No
2. Read SSR and check that bit RDRF is
set to 1. If it is, read the receive data in
RDR. When the RDR data is read, bit
RDRF is cleared to 0 automatically.
Read bit RDRF
in SSR
2
3. When continuing data reception, finish
reading of bit RDRF and RDR before
receiving the MSB (bit 7) of the current
frame. When the data in RDR is read,
bit RDRF is cleared to 0 automatically.
No
RDRF = 1?
Yes
4. If an overrun error has occurred, read bit
OER in SSR, and after carrying out the
necessary error processing, clear bit OER
to 0. Reception cannot be resumed if bit
OER is set to 1.
Read receive
data in RDR
Overrun error
processing
4
Yes
Continue data
reception?
3
No
Start overrun
error processing
Clear bit RE to
0 in SCR3
4
End
Overrun error
processing
Clear bit OER to
0 in SSR
End of overrun
error processing
Figure 10-18 Example of Data Reception Flowchart (Synchronous Mode)
308
ETC [ ETC ]
