HD6432621 Hitachi, HD6432621 Datasheet - Page 525

• Manufacturer Part Number: HD6432621
• Description: (HD64F262x Series) 16-Bit Microcomputer
• Manufacturer: Hitachi

Reception
Receive operation should be stopped (by clearing RE to 0) before making a module stop mode,
software standby mode, watch mode, subactive mode, or subsleep mode transition. RSR,
RDR, and SSR are reset. If a transition is made without stopping operation, the data being
received will be invalid.
To continue receiving without changing the reception mode after the relevant mode is cleared,
set RE to 1 before starting reception. To receive with a different receive mode, the procedure
must be started again from initialization.
Figure 13-26 shows a sample flowchart for mode transition during reception.
Read TEND flag in SSR
Figure 13-23 Sample Flowchart for Mode Transition during Transmission
<Start of transmission>
Transition to software
standby mode, etc.
standby mode, etc.
Exit from software
operating mode?
<Transmission>
Yes
Yes
Yes
transmitted?
Initialization
TEND = 1
Change
All data
TE = 0
[2]
No
No
No
TE = 1
[1]
[3]
[1] Data being transmitted is interrupted.
[2] If TIE and TEIE are set to 1, clear
[3] Includes module stop mode, watch
After exiting software standby mode,
etc., normal CPU transmission is
possible by setting TE to 1, reading
SSR, writing TDR, and clearing
TDRE to 0, but note that if the DTC
has been activated, the remaining
data in DTCRAM will be transmitted
when TE and TIE are set to 1.
them to 0 in the same way.
mode, subactive mode, and subsleep
mode.
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