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Section 13 Serial Communication Interface (SCI)
Read ORER flag in SSR
Read RDRF flag in SSR
No
Read receive data in RDR and
clear RDRF flag in SSR to 0
No
All data received?
Clear RE bit in SCR to 0
[3]
Overrun error processing
Clear ORER flag in SSR to 0
Rev. 1.00 Mar. 12, 2008 Page 472 of 1178
REJ09B0403-0100
Initialization
Start reception
ORER = 1
No
Error processing
(Continued below)
RDRF = 1
Yes
Yes
<End>
Error processing
<End>
Figure 13.19 Sample Serial Reception Flowchart
[1] SCI initialization:
[1]
The RxD pin is automatically
designated as the receive data input
pin.
[2] [3] Receive error processing:
If a receive error occurs, read the
[2]
ORER flag in SSR, and after
performing the appropriate error
Yes
processing, clear the ORER flag to 0.
[3]
Transfer cannot be resumed if the
ORER flag is set to 1.
[4] SCI status check and receive data
read:
Read SSR and check that the RDRF
[4]
flag is set to 1, then read the receive
data in RDR and clear the RDRF flag
to 0.
Transition of the RDRF flag from 0 to 1
can also be identified by an RXI
interrupt.
[5] Serial reception continuation
procedure:
To continue serial reception, before
the MSB (bit 7) of the current frame is
received, reading the RDRF flag,
reading RDR, and clearing the RDRF
[5]
flag to 0 should be finished.
However, the RDRF flag is cleared
automatically when the DTC is
initiated by a receive data full interrupt
(RXI) and reads data from RDR.
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