HD6473032F16 Datasheet, PDF (500/847 Pages) Renesas Technology Corp – Hardware Manual Renesas 16-Bit Single-Chip Microcomputer H8 Family/H8/300H Series

Section 13 Serial Communication Interface
• Receiving Serial Data (Asynchronous Mode)
Figure 13.7 shows a sample flowchart for receiving serial data and indicates the procedure to
follow.
Initialize
1
1. SCI initialization: the receive data function of
the RxD pin is selected automatically.
2, 3. Receive error handling and break
Start receiving
detection: if a receive error occurs, read the
ORER, PER, and FER flags in SSR to identify
the error. After executing the necessary error
Read ORER, PER,
and FER flags in SSR
2
handling, clear the ORER, PER, and FER
flags all to 0. Receiving cannot resume if any
of the ORER, PER, and FER flags remains
set to 1. When a framing error occurs, the
PER ∨ FER ∨
Yes
ORER = 1?
3
RxD pin can be read to detect the break state.
4. SCI status check and receive data read: read
SSR, check that RDRF is set to 1, then read
No
Error handling
receive data from RDR and clear the RDRF
flag to 0. Notification that the RDRF flag has
(continued on next page) _{changed from 0 to 1 can also be given by the}
Read RDRF flag in SSR 4
RXI interrupt.
5. To continue receiving serial data: check the
RDRF flag, read RDR, and clear the RDRF
No
RDRF = 1?
flag to 0 before the stop bit of the current
frame is received. If the DMAC is activated by
an RXI interrupt to read the RDR value, the
Yes
RDRF flag is cleared automatically.
Read receive data
from RDR, and clear
RDRF flag to 0 in SSR
No
Finished
receiving?
5
Yes
Clear RE bit to 0 in SCR
End
Figure 13.7 Sample Flowchart for Receiving Serial Data (1)
Rev. 3.00 Mar 21, 2006 page 470 of 814
REJ09B0302-0300