Renesas H8/3067 Series User Manual page 554

Section 13 Serial Communication Interface
• Receiving Serial Data (Synchronous Mode): Figure 13.18 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
Start receiving
Read ORER flag in SSR
ORER = 1
Read RDRF flag in SSR
No
RDRF = 1
Read receive data from
RDR, and clear RDRF
flag to 0 in SSR
No
Finished receiving?
Clear RE bit to 0 in SCR
<End>
Figure 13.18 Sample Flowchart for Serial Receiving (1)
Rev. 4.00 Jan 26, 2006 page 530 of 938
REJ09B0276-0400
(1)
(2)
Yes
No
Error handling
(continued on next page)
(4)
Yes
(5)
Yes
SCI initialization: the receive data
(1)
input function of the RxD pin is
selected automatically.
Receive error handling: if a receive
(2)(3)
error occurs, read the ORER flag in
SSR, then after executing the
necessary error handling, clear the
ORER flag to 0. Neither transmitting
nor receiving can resume while the
ORER flag remains set to 1.
(3)
SCI status check and receive data
(4)
read: read SSR, check that the RDRF
flag is set to 1, then read receive data
from RDR and clear the RDRF flag to
0. Notification that the RDRF flag
has changed from 0 to 1 can also be
given by the RXI interrupt.
To continue receiving serial data:
(5)
check the RDRF flag, read RDR, and
clear the RDRF flag to 0 before the
MSB (bit 7) of the current frame is
received. When the DMAC is
activated by a receive-data-full
interrupt request (RXI) to read RDR,
the RDRF flag is cleared
automatically.