HD6413007F20 Datasheet, PDF (538/798 Pages) Renesas Technology Corp – Hardware Manual Renesas 16-Bit Single-Chip Microcomputer H8 Family/H8/300H Series

14. Smart Card Interface
2. Write 0 in the TE and RE bits in the serial control register (SCR) to stop transmit/receive
operations. At the same time, set the CKE1 bit to the value for the fixed output state in
software standby mode.
3. Write 0 in the CKE0 bit in SCR to stop the clock.
4. Wait for one serial clock cycle. During this period, the duty cycle is preserved and clock output
is fixed at the specified level.
5. Write H'00 in the serial mode register (SMR) and smart card mode register (SCMR).
6. Make the transition to the software standby state.
• Returning from software standby mode to smart card interface mode
1′. Clear the software standby state.
2′. Set the CKE1 bit in SCR to the value for the fixed output state at the start of software standby
(the current P9₄ pin state).
3′. Set smart card interface mode and output the clock. Clock signal generation is started with the
normal duty cycle.
Normal operation
Software
standby
Normal operation
123
4 56
1′ 2′ 3′
Figure 14.10 Procedure for Stopping and Restarting the Clock
Use the following procedure to secure the clock duty cycle after powering on.
1. The initial state is port input and high impedance. Use pull-up or pull-down resistors to fix the
potential.
2. Fix at the output specified by the CKE1 bit in SCR.
3. Set SMR and SCMR, and switch to smart card interface mode operation.
4. Set the CKE0 bit to 1 in SCR to start clock output.
Rev.5.00 Sep. 12, 2007 Page 508 of 764
REJ09B0396-0500