HD6473032F16 Datasheet, PDF (546/847 Pages) Renesas Technology Corp – Hardware Manual Renesas 16-Bit Single-Chip Microcomputer H8 Family/H8/300H Series

Section 14 Smart Card Interface
Examples of Operation in GSM Mode: When switching between smart card interface mode and
software standby mode, use the following procedures to maintain the clock duty cycle.
• Switching from smart card interface mode to software standby mode
1. Set the P9₄ data register (DR) and data direction register (DDR) to the values for the fixed
output state in software standby mode.
2. Write 0 to 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 to 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 to 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
mode
Normal operation
(1)(2)(3)
(4) (5)(6)
(1) (2)(3)
Figure 14.9 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 in SCR to 1 to start clock output.
Rev. 3.00 Mar 21, 2006 page 516 of 814
REJ09B0302-0300