Hitachi H8/3637 Hardware Manual page 259

Transmitting: Figure 10.14 shows a typical flow chart for data transmission. After SCI3
initialization, follow the procedure below.
1 Read bit TDRE in SSR
TDRE = 1?
Write transmit data in TDR
Continue data transmission?
2
Read bit TEND in SSR
TEND = 1?
Write 0 to bit TE in SCR3
Figure 10.14 Typical Data Transmission Flow Chart in Synchronous Mode
Start
Yes
No
Yes
End
1. Read the serial status register (SSR),
and after confirming that bit TDRE = 1,
write transmit data in the transmit
data register (TDR).
No
When data is written to TDR, TDRE is
automatically cleared to 0.
If clock output has been selected, after
data is written to TDR, the clock is
output and data transmission begins.
Yes
2. To continue transmitting data, first read
TDRE to confirm that it is set to 1, indicating
that data writing is enabled; then write the
next data to TDR. When data is written to
TDR, TDRE is automatically cleared to 0.
No
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