H8S2604 Datasheet, PDF (436/574 Pages) Renesas Technology Corp – 16-Bit Single-Chip Microcomputer H8S Family/H8S/2600 Series

Section 15 Synchronous Serial Communication Unit (SSU)
Start
[1]
Initialization
[2]
Read TDRE in SSR
No
TDRE = 1?
Yes
Write transmit data to SSTDR
TDRE automatically cleared
Data transferd from SSTDR to SSTRSR
Set TDRE to 1 to start transmission
[3]
Yes
Continuous data transmission?
No
Read TEND in SSSR
TEND = 1?
Yes
Clear TEND to 0
No
Wait
Confirm TEND = 0
[4]
No
1-bit interval elapsed ?
Yes
Clear TE in SSER to 0
End transmission
[1] Initialization:
Specify the settings such as transmit
data format.
[2] Check the SSU state and write
transmit data:
Write transmit data to SSTDR after
reading and confirming that the TDRE bit
is 1. The TDRE bit is automatically cleared
to 0 and transmission is started by writing
data to SSTDR.
[3] Procedure for continuous data transmission:
To continue data transmission, confirm
that the TDRE bit is 1 meaning that SSTDR
is ready to be written to. After that, data can
be written to SSTDR. The TDRE bit is
automatically cleared to 0 by writing data to
SSTDR.
[4] Transmission end procedure:
To end transmission, confirm TEND = 1 and
wait until the last bit is surely transmitted,
then set TE to 0.
Note: Hatching boxes represent SSU internal operations.
Figure 15.6 Example of Data Transmission Flowchart
Rev. 1.00 Jan. 24, 2008 Page 400 of 534
REJ09B0426-0100