Section 16 Serial Communication Interface 3 (SCI3)
Start transmission/reception
Read TDRE flag in SSR
[1] Read SSR and check that the TDRE
flag is set to 1, then write transmit
data to TDR.
When data is written to TDR, the
TDRE flag is automatically cleared to
0.
[1]
No
[2] Read SSR and check that the RDRF
flag is set to 1, then read the receive
data in RDR.
TDRE = 1
Yes
When data is read from RDR, the
RDRF flag is automatically cleared to
0.
Write transmit data to TDR
Read OER flag in SSR
[3] To continue serial transmission/
reception, before the MSB (bit 7) of
the current frame is received, finish
reading the RDRF flag, reading RDR.
Also, before the MSB (bit 7) of the
current frame is transmitted, read 1
from the TDRE flag to confirm that
Yes
OER = 1
No
writing is possible. Then write data to
TDR.
[4]
Error processing
[2]
When data is written to TDR, the
TDRE flag is automatically cleared to
0. When data is read from RDR, the
RDRF flag is automatically cleared to
0.
Read RDRF flag in SSR
[4] If an overrun error occurs, read the
OER flag in SSR, and after
performing the appropriate error
processing, clear the OER flag to 0.
Transmission/reception cannot be
resumed if the OER flag is set to 1.
For overrun error processing, see
figure 16.13.
No
RDRF = 1
Yes
Read receive data in RDR
Yes
All data received?
No
[3]
Clear TE and RE bits in SCR to 0
<End>
Figure 16.14 Sample Flowchart of Simultaneous Serial Transmit and Receive Operations
(Clock Synchronous Mode)
Rev. 3.00 Sep. 10, 2007 Page 317 of 528
REJ09B0216-0300
RENESAS [ RENESAS TECHNOLOGY CORP ]
