RX610 Group
20. Serial Communications Interface (SCI)
R01UH0032EJ0120 Rev.1.20
Page 659 of 1006
Feb 20, 2013
Yes
No
Ini ialization
Start data transmission/reception
Error processing
Read receive data in RDR
No
Yes
ORER in SSR = 1
All data received?
No
Yes
TXI interrupt
Write transmit data to TDR
No
Yes
RXI interrupt
Read ORER flag in SSR
Clear the TIE, RIE, TE, RE,
and TEIE bits in SCR to 0
Note:
When switching from transmit or receive operation to simultaneous transmit and receive operations,
first clear the TIE, RIE, TE, RE, and TEIE bits in SCR to 0, and then set these bits to 1 simultaneously.
[ 1 ]
[ 2 ]
[ 3 ]
[ 1 ] SCI initialization:
The TxDn pin is designated as the transmit data output
pin, and the RxDn pin is designated as the receive data
input pin, enabling simultaneous transmit/receive
operations.
[ 2 ] Transmit data write:
Write transmit data to TDR once upon accep ing a TXI
interrupt request.
[ 3 ] Receive error processing:
If a receive error occurs, read the ORER flag in SSR,
perform the relevant error processing, and then clear the
ORER flag to 0. Data reception cannot be resumed while
the ORER flag is set to 1.
[ 4 ] Receive data read:
Read the receive data in RDR once upon accepting an
RXI interrupt request.
[ 5 ] Serial transmission/reception con inuation procedure:
To continue serial transmission/reception, before the
MSB (bit 7) of the current frame is received, finish reading
the receive data in RDR by the RXI interrupt. Also, before
the MSB (bit 7) of the current frame is transmitted, write
data to TDR by the TX interrupt.
Transmit data can also be written to TDR by initiating the
DMAC or DTC when a transmit data empty interrupt (TXI)
request is accepted. Similarly, the RDR data can also be
read by initiating the DMAC or DTC when a receive data
full interrupt (RXI) request is accepted.
[ 4 ]
[ 5 ]
End
Figure 20.19 Example of Simultaneous Serial Transmission/Reception Flowchart (Clock Synchronous Mode)