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10. Serial Communication Interface
Transmitting: Figure 10.10 shows a typical flow chart for data transmission. After SCI3
initialization, follow the procedure below.
Start
1
Read bit TDRE in SSR
TDRE = 1?
Write transmit data in TDR
Continue
2
data transmission?
Read bit TEND in SSR
TEND = 1?
3
Break output?
Set PDR = 0 and PCR = 1
Clear bit TE in SCR3 to 0
End
Figure 10.10 Typical Data Transmission Flow Chart (Asynchronous Mode)
Rev.3.00 Jul. 19, 2007 page 288 of 532
REJ09B0397-0300
No
Yes
Yes
No
No
Yes
No
Yes
1.
Read the serial status register (SRR),
and after confirming that bit TDRE = 1,
write transmit data in the transmit data
register (TDR). When data is written to
TDR, TDRE is automatically cleared to 0.
2.
To continue transmitting data, read bit TDRE
to make sure it is set to 1, then write the
next data to TDR. When data is written to
TDR, TDRE is automatically cleared to 0.
3.
To output a break signal when transmission
ends, first set the port values PCR = 1 and
PDR = 0, then clear bit TE in SCR3 to 0.
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