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Section 15 Serial Communication Interface (SCI)
SH7751 Group, SH7751R Group
Page 658 of 1128
R01UH0457EJ0301 Rev. 3.01
Sep 24, 2013
Serial Data Transmission (Synchronous Mode):
Figure 15.20 shows a sample flowchart for
serial transmission.
Use the following procedure for serial data transmission after enabling the SCI for transmission.
Start of transmission
Read TDRE fla
g
in SCSSR1
TDRE = 1?
All data transmitted?
Read TEND fla
g
in SCSSR1
Clear TE bit in SCSCR1 to 0
End
TEND = 1?
No
Yes
No
Yes
Yes
No
Write transmit data to SCTDR1
and clear TDRE fla
g
in SCSSR1 to 0
1. SCI status check and transmit
data write: Read SCSSR1 and
check that the TDRE fla
g
is set to
1, then write transmit data to
SCTDR1 and clear the TDRE fla
g
to 0.
2. To continue serial transmission,
be sure to read 1 from the TDRE
fla
g
to confirm that writin
g
is
possible, then write data to
SCTDR1, and then clear the
TDRE fla
g
to 0. (Checkin
g
and
clearin
g
of the TDRE fla
g
is
automatic when the direct
memory access controller
(DMAC) is activated by a
transmit-data-empty interrupt
(TXI) request, and data is written
to SCTDR1.)
Figure 15.20 Sample Serial Transmission Flowchart