HD6412240 RENESAS [Renesas Technology Corp], HD6412240 Datasheet - Page 502

• Manufacturer Part Number: HD6412240
• Description: Renesas 16-Bit Single-Chip Microcomputer H8S Family / H8S/2200 Series
• Manufacturer: RENESAS [Renesas Technology Corp]

Section 12 Serial Communication Interface (SCI)
In serial reception, the SCI operates as described below.
[1] The SCI performs internal initialization in synchronization with serial clock input or output.
[2] The received data is stored in RSR in LSB-to-MSB order.
[3] If the RIE bit in SCR is set to 1 when the RDRF flag changes to 1, a receive data full interrupt
Figure 12.19 shows an example of SCI operation in reception.
Simultaneous serial data transmission and reception (clocked synchronous mode): Figure
12.20 shows a sample flowchart for simultaneous serial transmit and receive operations.
The following procedure should be used for simultaneous serial data transmit and receive
operations.
Rev.3.00 Mar. 26, 2007 Page 460 of 772
REJ09B0355-0300
Serial
clock
Serial
data
RDRF
ORER
After reception, the SCI checks whether the RDRF flag is 0 and the receive data can be
transferred from RSR to RDR.
If this check is passed, the RDRF flag is set to 1, and the receive data is stored in RDR. If a
receive error is detected in the error check, the operation is as shown in table 12.11.
Neither transmit nor receive operations can be performed subsequently when a receive error
has been found in the error check.
(RXI) request is generated.
Also, if the RIE bit in SCR is set to 1 when the ORER flag changes to 1, a receive error
interrupt (ERI) request is generated.
RXI interrupt request
generated
Figure 12.19 Example of SCI Operation in Reception
Bit 7
RDR data read and
RDRF flag cleared to 0
in RXI interrupt service
routine
Bit 0
1 frame
Bit 7
Bit 0
RXI interrupt request
generated
Bit 1
ERI interrupt request
generated by overrun
error
Bit 6
Bit 7