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Transmitting
Figure 10-11 shows an example of a flowchart for data transmission. This procedure should be
followed for data transmission after initializing SCI3.
Start
Sets bits SPC31 and
SPC32 to 1 in SPCR
Read bit TDRE
1. Read the serial status register (SSR)
and check that bit TDRE is set to 1,
then write transmit data to the transmit
data register (TDR). When data is
written to TDR, bit TDRE is cleared to 0
automatically.
1
in SSR
No
TDRE = 1?
Yes
(After the TE bit is set to 1, one frame of
1s is output, then transmission is possible.)
2. When continuing data transmission,
be sure to read TDRE = 1 to confirm that
a write can be performed before writing
data to TDR. When data is written to
TDR, bit TDRE is cleared to 0
Write transmit
data to TDR
automatically.
Yes
Continue data
transmission?
2
3. If a break is to be output when data
transmission ends, set the port PCR to 1
and clear the port PDR to 0, then clear bit
TE in SCR3 to 0.
No
Read bit TEND
in SSR
No
No
TEND = 1?
Yes
3
Break output?
Yes
Set PDR = 0,
PCR = 1
Clear bit TE to 0
in SCR3
End
Figure 10-11 Example of Data Transmission Flowchart (Asynchronous Mode)
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ETC [ ETC ]
