H8SX1657 Datasheet, PDF (627/892 Pages) Renesas Technology Corp – Renesas 32-Bit CISC Microcomputer H8SX Family / H8SX/1600 Series

Section 14 Serial Communication Interface (SCI)
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]
Read TEND flag in SSR
[1] SCI initialization:
The TxD pin is automatically
designated as the transmit data output
pin.
[2] SCI state 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. However, the TDRE
flag is checked and cleared
automatically when the DMAC or DTC
is initiated by a transmit data empty
interrupt (TXI) request and writes data
to TDR.
No
TEND = 1
Yes
Clear TE bit in SCR to 0
<End>
Figure 14.17 Sample Serial Transmission Flowchart
Rev. 2.00 Jun. 28, 2007 Page 603 of 864
REJ09B0341-0200