h8s-2138 Renesas Electronics Corporation., h8s-2138 Datasheet - Page 499

• Manufacturer Part Number: h8s-2138
• Description: Renesas 16-bit Single-chip Microcomputer H8s Family/h8s/2100 Series
• Manufacturer: Renesas Electronics Corporation.

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 15.19 shows an example of SCI operation in reception.
Simultaneous Serial Data Transmission and Reception (Synchronous Mode): Figure 15.20
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.
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 15.11.
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 15.19 Example of SCI Operation in Reception
Bit 7
RDR data read and
RDRF flag cleared to 0
in RXI interrupt handling
routine
Bit 0
1 frame
Section 15 Serial Communication Interface (SCI, IrDA)
Bit 7
Bit 0
RXI interrupt request
generated
Rev. 4.00 Jun 06, 2006 page 445 of 1004
Bit 1
ERI interrupt request
generated by overrun
error
Bit 6
REJ09B0301-0400
Bit 7