Renesas Hitachi H8S/2194 Series Hardware Manual page 515

(b) Serial Data Transmission (Clock Synchronous Mode)
Figure 23.16 shows a sample flowchart for serial transmission.
The following procedure should be used for serial data transmission.
Initialization
Start transmission
Read TDRE flag in SSR1
TDRE=1
Write transmit data to TDR1 and
clear TDRE flag in SSR1 to 0
All data transmitted?
Read TEND flag in SSR1
TEND=1
Clear TE bit in
SCR1 to 0
< End >
Figure 23.16 Sample Serial Transmission Flowchart
Rev. 2.0, 11/00, page 488 of 1037
No
Yes
No
Yes
No
Yes
SCI1 initialization:
[1] [1]
The SO1 pin is automatically designated as
the transmit data output pin.
SCI1 status check and transmit data write:
[2]
Read SSR1 and check that the TDRE flag
[2] is set to 1, then write transmit data to TDR1
and clear the TDRE flag to 0.
Serial transmission continuation procedure:
[3]
To continue serial transmission, be sure to
read 1 from the TDRE flag to confirm that
writing is possible, then write data to TDR1,
and then clear the TDRE flag to 0.
[3]