Rev. 1.0, 07/01, page 205 of 372
No
Yes
Start transmission
Read TDRE flag in SSR[1]
Write transmit data to TDR
No
Yes
No
Yes
Read TEND flag in SSR
[2]
Clear TE bit in SCR3 to 0
TDRE = 1
All data transmitted?
TEND = 1
[1] Read SSR and check that the TDRE flag is
set to 1, then write transmit data to TDR
and clear the TDRE flag to 0. When data is
written to TDR, the TDRE flag is
automatically cleared to 0 and clocks are
output to start the data transmission.
[2] To continue serial transmission, be sure to
read 1 from the TDRE flag to confirm that
writing is possible, then write data to TDR.
When data is written to TDR, the TDRE flag
is automatically cleared to 0.
End
Figure 14-11 Sample Serial Transmission Flowchart (Clocked Synchronous Mode)