Rev. 1.0, 09/02, page 350 of 568
When turning on the power or switching between Smart Card interface mode and software
standby mode, the following procedures should be followed in order to maintain the clock duty
cycle.
Powering On: To secure clock duty cycle from power-on, the following switching procedure
should be followed.
1. The initial state is port input and high impedance. Use a pull-up resistor or pull-down
resistor to fix the potential.
2. Fix the SCK pin to the specified output level with the CKE1 bit in SCR.
3. Set SMR and SCMR, and switch to smart card mode operation.
4. Set the CKE0 bit in SCR to 1 to start clock output.
When changing from smart card interface mode to software standby mode:
1. Set the data register (DR) and data direction register (DDR) corresponding to the SCK pin
to the value for the fixed output state in software standby mode.
2. Write 0 to the TE bit and RE bit in the serial control register (SCR) to halt transmit/receive
operation. 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 halt the clock.
4. Wait for one serial clock period.
During this interval, clock output is fixed at the specified level, with the duty cycle
preserved.
5. Make the transition to the software standby state.
When returning to smart card interface mode from software standby mode:
1. Exit the software standby state.
2. Write 1 to the CKE0 bit in SCR and output the clock. Signal generation is started with the
normal duty cycle.
[1] [2] [3]
[4] [5]
[7]
Software
standby
Normal operation
Normal operation
[6]
Figure 14.32 Clock Halt and Restart Procedure
Содержание H8S/2627
Страница 22: ...Rev 1 0 09 02 page xx of xxxvi Index 565 ...
Страница 30: ...Rev 1 0 09 02 page xxviii of xxxiv ...
Страница 36: ...Rev 1 0 09 02 page xxxiv of xxxiv Table 23 9 Flash Memory Characteristics 561 ...
Страница 82: ...Rev 1 0 09 02 page 46 of 568 ...
Страница 88: ...Rev 1 0 09 02 page 52 of 568 ...
Страница 98: ...Rev 1 0 09 02 page 62 of 568 ...
Страница 156: ...Rev 1 0 09 02 page 120 of 568 ...
Страница 390: ...Rev 1 0 09 02 page 354 of 568 ...
Страница 480: ...Rev 1 0 09 02 page 444 of 568 ...
Страница 512: ...Rev 1 0 09 02 page 476 of 568 ...
Страница 527: ...Rev 1 0 09 02 page 491 of 568 21 8 5 Writing to MSTPCR MSTPCR should only be written to by the CPU ...
Страница 528: ...Rev 1 0 09 02 page 492 of 568 ...
Страница 580: ...Rev 1 0 09 02 page 544 of 568 ...