HD64F3670 Datasheet, PDF (195/305 Pages) Renesas Technology Corp – Hitachi Single-Chip Microcomputer

Start transmission
[1]
Read TDRE flag in SSR
No
TDRE = 1
Yes
Write transmit data to TDR
Yes
[2]
All data transmitted?
No
Read TEND flag in SSR
No
TEND = 1
Yes
No
[3]
Break output?
Yes
Clear PDR to 0 and
set PCR to 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. Checking and
clearing of the TDRE flag is
automatic.
[2] To continue serial transmission,
read 1 from the TDRE flag to
confirm that writing is possible,
then write data to TDR, and then
clear the TDRE flag to 0. Checking
and clearing of the TDRE flag is
automatic.
[3] To output a break in serial
transmission, set PCR to 1 and
PDR to 0, clear TXD in PMR1 to 0,
then clear the TE bit in SCR3 to 0.
Clear TE bit in SCR3 to 0
<End>
Figure 13-6 Sample Serial Transmission Flowchart
Rev. 1.0, 03/01, page 171 of 280