H8S2556 Datasheet, PDF (498/982 Pages) Renesas Technology Corp – 16-Bit Single-Chip Microcomputer H8S Family/H8S/2500 Series

Section 13 Serial Communication Interface (SCI)
Initialization
Start reception
[1]
[1] SCI initialization:
The RxD pin is automatically
designated as the receive data input
pin.
Read ORER flag in SSR
ORER = 1
[2]
Yes
[3]
[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.
No
Error processing ^{[4] SCI status check and receive data}
read:
(Continued below)
Read SSR and check that the RDRF
flag is set to 1, then read the receive
Read RDRF flag in SSR
[4]
data in RDR and clear the RDRF flag
to 0.
Transition of the RDRF flag from 0 to 1
No
RDRF = 1
can also be identified by an RXI
interrupt.
Yes
Read receive data in RDR, and
clear RDRF flag in SSR to 0
No
All data received?
Yes
Clear RE bit in SCR to 0
<End>
[5] Serial reception continuation
procedure:
To continue serial reception, before
the final bit 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
[5]
receive data full interrupt (RXI) request
and the RDR value is read.
Note: * The case, where the RDRF flag check and
clearing are automatically executed by DTC,
occurs only when the DISEL bit in DTC is 0
with the transfer counter other than 0.
Therefore, when the DISEL bit is 1, or
both the DISEL bit and the transfer counter are 0,
give the CPU an instruction to clear the RDRF flag.
[3]
Error processing
Overrun error processing
Clear ORER flag in SSR to 0
<End>
Figure 13.19 Sample Serial Reception Flowchart
Rev.5.00 Sep. 27, 2007 Page 452 of 932
REJ09B0099-0500