3069RF-ZTAT Datasheet, PDF (524/1003 Pages) Renesas Technology Corp – RENESAS 16-BIT 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
Start transmitting
Read TDRE flag in SSR
(1) (1) ^{SCI initialization: the transmit data output}
function of the TxD pin is selected
automatically.
(2) SCI status check and transmit data write:
read SSR, check that the TDRE flag is 1, then
(2)
write transmit data in TDR and clear the
TDRE flag to 0.
TDRE = 1
No
Yes
Write transmit data in TDR
and clear TDRE flag to 0 in SSR
(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?
No
(3)
Yes
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
Rev. 5.0, 09/04, page 502 of 978