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Section 13 Serial Communication Interface (SCI)
At Transition from Smart Card Interface Mode to Software Standby Mode:
1. Set the port data register (DR) and data direction register (DDR) corresponding to the SCK
pins to the values for the output fixed state in software standby mode.
2. Write 0 to the TE and RE bits in SCR to stop transmission/reception. Simultaneously, set the
CKE1 bit to the value for the output fixed state in software standby mode.
3. Write 0 to the CKE0 bit in SCR to stop the clock.
4. Wait for one cycle of the serial clock. In the mean time, the clock output is fixed to the
specified level with the duty ratio retained.
5. Make the transition to software standby mode.
At Transition from Software Standby Mode to Smart Card Interface Mode:
1. Cancel software standby mode.
2. Write 1 to the CKE0 bit in SCR to start clock output. A clock signal with the appropriate duty
ratio is then generated.
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Rev. 1.00 Mar. 12, 2008 Page 486 of 1178
REJ09B0403-0100
Normal operation
[4] [5]
Figure 13.32 Clock Stop and Restart Procedure
Software
Normal operation
standby
[1]
[2]
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