h8s-2649 Renesas Electronics Corporation., h8s-2649 Datasheet - Page 453

• Manufacturer Part Number: h8s-2649
• Description: Renesas 16-bit Single-chip Microcomputer H8s Family/h8s/2600 Series
• Manufacturer: Renesas Electronics Corporation.

13.9.5
When the external clock source is used as a synchronization clock, update TDR by the DTC and
wait for at least five φ clock cycles before allowing the transmit clock to be input. If the transmit
clock is input within four clock cycles after TDR modification, the SCI may malfunction (figure
13.33).
When using the DTC to read RDR, be sure to set the receive end interrupt source (RXI) as a DTC
activation source.
13.9.6
Transmission: Before making the transition to module stop, software standby, watch, sub-active,
or sub-sleep mode, stop all transmit operations (TE = TIE = TEIE = 0). TSR, TDR, and SSR are
reset. The states of the output pins during each mode depend on the port settings, and the pins
output a high-level signal after mode is cancelled and then the TE is set to 1 again. If the transition
is made during data transmission, the data being transmitted will be undefined.
To transmit data in the same transmission mode after mode cancellation, set TE to 1, read SSR,
write to TDR, clear TDRE in this order, and then start transmission. To transmit data in a different
transmission mode, initialize the SCI first.
Figure 13.34 shows a sample flowchart for mode transition during transmission. Figures 13.35 and
13.36 show the pin states during transmission.
Before making the transition from the transmission mode using DTC transfer to module stop,
software standby, watch, sub-active, or sub-sleep mode, stop all transmit operations (TE = TIE =
Figure 13.33 Sample Transmission using DTC in Clocked Synchronous Mode
Restrictions on Using DTC
SCI Operations during Mode Transitions
SCK
TDRE
Serial data
Note: When external clock is supplied, t must be more than four clock cycles.
t
LSB
D0
D1
D2
D3
Section 13 Serial Communication Interface (SCI)
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Rev. 2.00 Dec. 05, 2005 Page 415 of 724
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D6
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REJ09B0200-0200