Figure 15.9 Sample Serial Reception Flowchart (1) - Renesas H8S Series Hardware Manual

Section 15 Serial Communication Interface (SCI, IrDA)
Read ORER, PER, and
FER flags in SSR
PER ∨ FER ∨ ORER = 1
Read RDRF flag in SSR
No
Read receive data in RDR, and
clear RDRF flag in SSR to 0
No
All data received?
Clear RE bit in SCR to 0
Rev. 3.00 Jul. 14, 2005 Page 464 of 986
REJ09B0098-0300
Initialization
Start reception
No
Error processing
(Continued on next page)
RDRF = 1
Yes
Yes
<End>

Figure 15.9 Sample Serial Reception Flowchart (1)

[1] SCI initialization:
[1]
The RxD pin is automatically
designated as the receive data input
pin.
[2] [3] Receive error processing and break
detection:
[2]
If a receive error occurs, read the
ORER, PER, and FER flags in SSR to
identify the error. After performing the
Yes
appropriate error processing, ensure
that the ORER, PER, and FER flags are
[3]
all cleared to 0. Reception cannot be
resumed if any of these flags are set to
1. In the case of a framing error, a
break can be detected by reading the
value of the input port corresponding to
[4]
the RxD pin.
[4] SCI status check and receive data read:
Read SSR and check that RDRF = 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
stop bit for the current frame is
received, read the RDRF flag, read
[5]
RDR, and clear the RDRF flag to 0.
However, the RDRF flag is cleared
automatically when the DTC is initiated
by an RXI interrupt and reads data from
RDR.
Legend
∨ : Logical add (OR)