Datasheet
Section 16 Serial Communication Interface (SCI, IrDA)
(The H8S/2695 is not equipped with an IrDA function)
Page 796 of 1434 R01UH0166EJ0600 Rev. 6.00
Mar 02, 2011
H8S/2633 Group, H8S/2633 F-ZTAT
TM
,
H8S/2633R F-ZTAT
TM
, H8S/2695
Operation in Case of Mode Transition
• Transmission
Operation should be stopped (by clearing TE, TIE, and TEIE to 0) before making a module
stop mode, software standby mode, watch mode, subactive mode, or subsleep mode transition.
TSR, TDR, and SSR are reset. The output pin states in module stop mode, software standby
mode, watch mode, subactive mode, or subsleep mode depend on the port settings, and
becomes high-level output after the relevant mode is cleared. If a transition is made during
transmission, the data being transmitted will be undefined. When transmitting without
changing the transmit mode after the relevant mode is cleared, transmission can be started by
setting TE to 1 again, and performing the following sequence: SSR read -> TDR write ->
TDRE clearance. To transmit with a different transmit mode after clearing the relevant mode,
the procedure must be started again from initialization. Figure 16.25 shows a sample flowchart
for mode transition during transmission. Port pin states are shown in figures 16.26 and 16.27.
Operation should also be stopped (by clearing TE, TIE, and TEIE to 0) before making a
transition from transmission by DTC
*
transfer to module stop mode, software standby mode,
watch mode
*
, subactive mode
*
, or subsleep mode
*
transition. To perform transmission with
the DTC
*
after the relevant mode is cleared, setting TE and TIE to 1 will set the TXI flag and
start DTC
*
transmission.
Note: * The DTC is not available in the H8S/2695.
• 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 16.28 shows a sample flowchart for mode transition during reception.