HD64F3670 Datasheet, PDF (202/305 Pages) Renesas Technology Corp – Hitachi Single-Chip Microcomputer

Start transmission
[1] Read SSR and check that the TDRE flag is
set to 1, then write transmit data to TDR
[1]
Read TDRE flag in SSR
and clear the TDRE flag to 0. When data is
written to TDR, the TDRE flag is
automatically cleared to 0 and clocks are
TDRE = 1
No
output to start the data transmission.
[2] To continue serial transmission, be sure to
read 1 from the TDRE flag to confirm that
Yes
writing is possible, then write data to TDR.
When data is written to TDR, the TDRE flag
Write transmit data to TDR
is automatically cleared to 0.
No
[2]
All data transmitted?
Yes
Read TEND flag in SSR
No
TEND = 1
Yes
Clear TE bit in SCR3 to 0
<End>
Figure 13-11 Sample Serial Transmission Flowchart(Clocked Synchronous Mode)
Rev. 1.0, 03/01, page 178 of 280