H8S2189R Datasheet, PDF (478/812 Pages) Renesas Technology Corp – Renesas 16-Bit Single-Chip Microcomputer H8S Family / H8S/2100 Series

Section 14 Serial Communication Interface (SCI, IrDA)
Initialization
[1]
Start transmission
Read TDRE flag in SSR
[2]
No
TDRE = 1
Yes
Write transmit data to TDR and
clear TDRE flag in SSR to 0
All data transmitted?
Yes
No
[3]
[1] SCI initialization:
The TxD pin is automatically
designated as the transmit data output
pin.
[2] SCI status check and transmit data
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.
Read TEND flag in SSR
No
TEND = 1
Yes
Clear TE bit in SCR to 0
<End>
Figure 14.17 Sample Serial Transmission Flowchart
Rev. 2.00 Aug. 03, 2005 Page 436 of 766
REJ09B0223-0200