Figure 16.17 Sample Serial Transmission Flowchart - Renesas H8S/2437 Hardware Manual

Initialization
Start transmission
Read TDRE flag in SSR
TDRE = 1
Write transmit data to TDR and
clear TDRE flag in SSR to 0
All data transmitted?
Read TEND flag in SSR
TEND = 1
Clear TE bit in SCR to 0
Rev. 1.00, 09/03, page 462 of 704
No
Yes
No
Yes
No
Yes
<End>

Figure 16.17 Sample Serial Transmission Flowchart

[1] SCI initialization:
[1]
The TxD pin is automatically
designated as the transmit data output
pin.
[2] SCI status check and transmit data
[2]
write:
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.
[3] Serial transmission continuation
procedure:
To continue serial transmission, be
sure to 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.
[3]