HD6433044 Hitachi Semiconductor, HD6433044 Datasheet - Page 495

• Manufacturer Part Number: HD6433044
• Description: (HD64 Series) Hitachi Single-Chip Microcomputer
• Manufacturer: Hitachi Semiconductor

Transmitting Serial Data (Synchronous Mode): Figure 13-16 shows a sample flowchart for
transmitting serial data and indicates the procedure to follow.
TDR and clear TDRE flag
Read TDRE flag in SSR
Read TEND flag in SSR
Clear TE bit to 0 in SCR
Write transmit data in
Start transmitting
transmitted?
to 0 in SSR
TDRE = 1?
TEND = 1?
Initialize
All data
End
Yes
Yes
Yes
Figure 13-16 Sample Flowchart for Serial Transmitting
No
No
No
1
2
3
1.
2.
3.
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.
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.
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.
484