HD6413008VF25 Datasheet, PDF (403/688 Pages) Renesas Technology Corp – Old Company Name in Catalogs and Other Documents

12. Serial Communication Interface
• Transmitting Serial Data (Asynchronous Mode): Figure 12.5 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
All data transmitted?
Yes
Read TEND flag in SSR
No
(3)
TEND = 1
Yes
Output break signal?
No
No ₍₄₎
(1) SCI initialization:
the transmit data output function of
the TxD pin is selected automatically.
After the TE bit is set to 1, one frame
of 1s is output, then transmission is
possible.
(2) SCI status check and transmit data
write:
read SSR and check that the TDRE
flag is set to 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.
(4) To output a break signal at the end of
serial transmission:
set the DDR bit to 1 and clear the DR
bit to 0, then clear the TE bit to 0 in
SCR.
Yes
Clear DR bit to 0 and set
DDR bit to 1
Clear TE bit to 0 in SCR
<End>
Figure 12.5 Sample Flowchart for Transmitting Serial Data
Rev.4.00 Aug. 20, 2007 Page 357 of 638
REJ09B0395-0400