Figure 14.19 Sample Serial Reception Flowchart - Hitachi H8S/2628 Hardware Manual

Initialization
Start reception
Read ORER flag in SSR
ORER = 1
Read RDRF flag in SSR
No
RDRF = 1
Read receive data in RDR, and
clear RDRF flag in SSR to 0
No
All data received?
Clear RE bit in SCR to 0
<End>
[3]
Error processing
Overrun error processing
Clear ORER flag in SSR to 0
<End>

Figure 14.19 Sample Serial Reception Flowchart

[1]
[2]
Yes
[3]
No
Error processing
(Continued below)
[4]
Yes
[5]
Yes
[1] SCI initialization:
The RxD pin is automatically
designated as the receive data input
pin.
[2] [3] Receive error processing:
If a receive error occurs, read the
ORER flag in SSR, and after
performing the appropriate error
processing, clear the ORER flag to 0.
Transfer cannot be resumed if the
ORER flag is set to 1.
[4] SCI status check and receive data
read:
Read SSR and check that the RDRF
flag is set to 1, then read the receive
data in RDR and clear the RDRF flag
to 0.
Transition of the RDRF flag from 0 to 1
can also be identified by an RXI
interrupt.
[5] Serial reception continuation
procedure:
To continue serial reception, before
the MSB (bit 7) of the current frame is
received, reading the RDRF flag,
reading RDR, and clearing the RDRF
flag to 0 should be finished. The
RDRF flag is cleared automatically
when the DTC is activated by a
receive data full interrupt (RXI) request
and the RDR value is read.
Rev. 1.0, 09/02, page 337 of 568