Filter
Top Products
Section 15 Serial Communication Interface with FIFO
R01UH0134EJ0400 Rev. 4.00 Page 769 of 2108
Sep 24, 2014
SH7262 Group, SH7264 Group
Transmitting and Receiving Serial Data Simultaneously (Clock Synchronous Mode)
Figure 15.18 shows a sample flowchart for transmitting and receiving serial data
simultaneously.
Use the following procedure for the simultaneous transmission/reception of serial data, after
enabling transmit/receive operation.
Start of transmission and reception
Initialization
Read TDFE flag in SCFSR
TDFE = 1?
Write transmit data to SCFTDR,
read TDFE and TEND flags
in SCFSR as 1,
and then clear the flags to 0
Read ORER flag in SCLSR
ORER = 1?
Read RDF flag in SCFSR
RDF = 1?
Clear TE and RE bits
in SCSCR to 0
End of transmission and reception
Read receive data in
SCFRDR, and clear RDF
flag in SCFSR to 0
All data received?
No
No
Yes
No
No
Yes
Yes
[1] Status check and transmit data write:
Read SCFSR and check that the
TDFE flag is set to 1, then write
transmit data to SCFTDR. Clear the
TDFE and TEND flags to 0 after
reading them as 1. The transition of
the TDFE flag from 0 to 1 can also be
identified by
a transmit FIFO data
empty interrupt (TXI).
[2] Receive error handling:
Read the ORER flag in SCLSR to
identify any error, perform the
appropriate error handling, then clear
the ORER flag to 0. Reception cannot
be resumed while the ORER flag is
set to 1.
[3] Status check and receive data read:
Read SCFSR and check that RDF
flag = 1, then read the receive data in
SCFRDR, and clear the RDF flag to
0. The transition of the RDF flag from
0 to 1 can also be identified by
a
receive FIFO data full interrupt
(RXI).
[4] Serial transmission and reception
continuation procedure:
To continue serial transmission and
reception, read 1 from the RDF flag
and the receive data in SCFRDR, and
clear the RDF flag to 0 before
receiving the MSB in the current
frame. Similarly, read 1 from the
TDFE flag to confirm that writing is
possible before transmitting the MSB
in the current frame. Then write data
to SCFTDR and clear the TDFE flag
to 0.
[1]
Yes
Error handling
[4]
When switching from a transmit operation
or receive operation to simultaneous
transmission and reception operations,
clear the TE and RE bits to 0, and then
set them simultaneously to 1.
Note:
[3]
[2]
Figure 15.18 Sample Flowchart for Transmitting/Receiving Serial Data