HD643303x Hitachi, HD643303x Datasheet - Page 366

• Manufacturer Part Number: HD643303x
• Description: Hitachi Microcomputer
• Manufacturer: Hitachi

Transmitting and Receiving Data
Transmitting Multiprocessor Serial Data: Figure 11-10 shows a sample flowchart for
transmitting multiprocessor serial data and indicates the procedure to follow.
Clear DR bit to 0, set DDR bit to 1
TDR and set MPBT bit in SSR
Figure 11-10 Sample Flowchart for Transmitting Multiprocessor Serial Data
Read TDRE flag in SSR
Read TEND flag in SSR
Clear TE bit to 0 in SCR
Write transmit data in
Clear TDRE flag to 0
Output break signal?
All data transmitted?
Start transmitting
TDRE = 1?
TEND = 1?
Initialize
End
Yes
Yes
Yes
Yes
No
No
No
No
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SCI initialization: the transmit data
output function of the TxD pin is
selected automatically.
SCI status check and transmit data
write: read SSR, check that the TDRE
flag is 1, then write transmit
data in TDR. Also set the MPBT flag to
0 or 1 in SSR. Finally, 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.
To output a break signal at the end of
serial transmission: set the DDR bit to
1 and clear the DR bit to 0 (DDR and
DR are I/O port registers), then clear
the TE bit to 0 in SCR.