HD6413008VF25 Datasheet, PDF (419/688 Pages) Renesas Technology Corp – Old Company Name in Catalogs and Other Documents

12. Serial Communication Interface
• Receiving Serial Data (Synchronous Mode): Figure 12.18 shows a sample flowchart for
receiving serial data and indicates the procedure to follow. When switching from asynchronous
to synchronous mode, make sure that the ORER, PER, and FER flags are cleared to 0. If the
FER or PER flag is set to 1 the RDRF flag will not be set and both transmitting and receiving
will be disabled.
Initialize
(1)
(1) SCI initialization: the receive data
input function of the RxD pin is
Start receiving
selected automatically.
(2)(3) Receive error handling: if a receive
Read ORER flag in SSR
(2)
error occurs, read the ORER flag in
SSR, then after executing the
necessary error handling, clear the
ORER = 1
Yes
ORER flag to 0. Neither transmitting
nor receiving can resume while the
ORER flag remains set to 1.
No
(3)
Error handling
(4)
(continued on next page)
SCI status check and receive data
read: read SSR, check that the RDRF
flag is set to 1, then read receive data
Read RDRF flag in SSR
(4)
from RDR and clear the RDRF flag to
0. Notification that the RDRF flag
has changed from 0 to 1 can also be
No
RDRF = 1
given by the RXI interrupt.
Yes
Read receive data from
RDR, and clear RDRF
flag to 0 in SSR
(5) To continue receiving serial data:
check the RDRF flag, read RDR, and
clear the RDRF flag to 0 before the
MSB (bit 7) of the current frame is
received.
No
Finished receiving?
(5)
Yes
Clear RE bit to 0 in SCR
<End>
Figure 12.18 Sample Flowchart for Serial Receiving (1)
Rev.4.00 Aug. 20, 2007 Page 373 of 638
REJ09B0395-0400