Datasheet

Section 17 Smart Card Interface
Page 830 of 1434 R01UH0166EJ0600 Rev. 6.00
Mar 02, 2011
H8S/2633 Group, H8S/2633 F-ZTAT
TM
,
H8S/2633R F-ZTAT
TM
, H8S/2695
17.3.7 Operation in GSM Mode
Switching the Mode: When switching between smart card interface mode and software standby
mode, the following switching procedure should be followed in order to maintain the clock duty.
• 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 preserved.
[5] Make the transition to the software standby state.
• When returning to smart card interface mode from software standby mode
[6] Exit the software standby state.
[7] Write 1 to the CKE0 bit in SCR and output the clock. Signal generation is started with the
normal duty.
[1] [2] [3] [4] [5] [6] [7]
Software
standby
Normal operation Normal operation
Figure 17.9 Clock Halt and Restart Procedure