HD6433044 Datasheet, PDF (495/867 Pages) Hitachi Semiconductor – Hitachi Single-Chip Microcomputer

Transmitting Serial Data (Synchronous Mode): Figure 13-16 shows a sample flowchart for
transmitting serial data and indicates the procedure to follow.
Initialize
1
Start transmitting
Read TDRE flag in SSR
2
No
TDRE = 1?
Yes
Write transmit data in
TDR and clear TDRE flag
to 0 in SSR
1. SCI initialization: the transmit data output function
of the TxD pin is selected automatically. After setting
TE bit to 1, output 1 from frame one transmission is
possible.
2. SCI status check and transmit data write: read SSR,
check that the TDRE flag is 1, then write transmit
data in TDR and clear the TDRE flag to 0.
3. To continue transmitting serial data: after checking
that the TDRE flag is 1, indicating that data can be
written, write data in TDR, then clear the TDRE flag
to 0. When the DMAC is activated by a transmit-
data-empty interrupt request (TXI) to write data in
TDR, the TDRE flag is checked and cleared
automatically.
All data
transmitted?
Yes
No
3
Read TEND flag in SSR
No
TEND = 1?
Yes
Clear TE bit to 0 in SCR
End
Figure 13-16 Sample Flowchart for Serial Transmitting
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