SH7144_08 Datasheet, PDF (492/930 Pages) Renesas Technology Corp – 32-Bit RISC Microcomputer SuperHTM RISC engine Family/SH7144 Series

13. Serial Communication Interface (SCI)
Reception cannot be resumed while a receive error flag is set to 1. Accordingly, clear the ORER,
FER, PER, and RDRF bits to 0 before resuming reception. Figure 13.19 shows a sample flowchart
for serial data reception.
An overrun error occurs or synchronous clocks are output until the RE bit is cleared to 0 when an
internal clock is selected and only receive operation is possible. When reception will be carried out
in a unit of one frame, be sure to carry out a dummy transmission with only one frame by the
simultaneous transmit and receive operations at the same time.
Initialization
[1] SCI initialization:
[1]
Set the RxD pin using the PFC.
Start reception
[2] [3] Receive error processing:
If a receive error occurs, read the
ORER flag in SSR, and after
Read ORER flag in SSR
[2]
performing the appropriate error
processing, clear the ORER flag to 0.
Transfer cannot be resumed if the
ORER = 1
Yes
[3]
ORER flag is set to 1.
[4] SCI status check and receive data
No
Error processing
read:
Read SSR and check that the RDRF
(Continued below)
flag is set to 1, then read the receive
data in RDR and clear the RDRF flag
Read RDRF flag in SSR
[4]
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?
[5]
Yes
[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 DMAC or DTC is activated
by a receive data full interrupt (RXI)
request and the RDR value is read.
Clear RE bit in SCR to 0
<End>
[3]
Error processing
Overrun error processing
Clear ORER flag in SSR to 0
<End>
Figure 13.19 Sample Serial Reception Flowchart
Rev.4.00 Mar. 27, 2008 Page 448 of 882
REJ09B0108-0400