RX610 Group
20. Serial Communications Interface (SCI)
R01UH0032EJ0120 Rev.1.20
Page 671 of 1006
Feb 20, 2013
(1) At Power-On
To secure the appropriate clock duty cycle simultaneously with power-on, use the following procedure.
1. Initially, port input is enabled in the high-impedance state. To fix the potential level, use a pull-up or pull-down
resistor.
2. Fix the SCKn pin to the specified output using the CKE1 bit in SCR.
3. Set SMR and SCMR to enable smart card interface mode. Set the CKE0 bit in SCR to 1 to start clock output.
(2) At Mode Switching
(a) At transition from smart card interface mode to software standby mode
1. Set the data register (DR of Pm) and data direction register (DDR of Pm) corresponding to the SCKn pin 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 in SCR 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 stops and is fixed low level after the
specified high-level period is output.
5. Make a transition to software standby mode.
(b) At transition from software standby mode to smart card interface mode
1. Cancel software standby mode.
2. Set the CKE0 bit in SCR to 1. The clock output with the specified frequency is then re-started.
[2]
[1]
[3]
[4]
[5]
[6]
[7]
Software
standby
Normal operation
Normal operation
SCKn
Figure 20.31 Clock Stop and Restart Procedure
Summary of Contents for RX600 Series
Page 1006: ...RX610 Group R01UH0032EJ0120 ...