D12320VF25V Datasheet, PDF (520/1146 Pages) Renesas Technology Corp – Old Company Name in Catalogs and Other Documents

Section 12 Serial Communication Interface (SCI)
Figure 12.17 shows an example of SCI operation in transmission.
Serial clock
Transfer direction
Serial data
Bit 7 Bit 0
Bit 7 Bit 0 Bit 1
Bit 6 Bit 7
TDRE
TEND
TXI interrupt
request generated
Data written to TDR TXI interrupt
and TDRE flag
request generated
cleared to 0 in TXI
interrupt handling routine
TEI interrupt
request generated
1 frame
Figure 12.17 Example of SCI Transmit Operation
Serial data reception (synchronous mode): Figure 12.18 shows a sample flowchart for serial
reception.
The following procedure should be used for serial data reception.
When changing the operating mode from asynchronous to synchronous, be sure to check that the
ORER, PER, and FER flags are all cleared to 0.
The RDRF flag will not be set if the FER or PER flag is set to 1, and neither transmit nor receive
operations will be possible.
Rev.7.00 Feb. 14, 2007 page 486 of 1108
REJ09B0089-0700