HD6412320 RENESAS [Renesas Technology Corp], HD6412320 Datasheet - Page 724

• Manufacturer Part Number: HD6412320
• Description: Renesas 16-Bit Single-Chip Microcomputer H8S Family H8S-2300 Series
• Manufacturer: RENESAS [Renesas Technology Corp]

Section 15 Smart Card Interface
15.3.7
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
[2] Write 0 to the TE bit and RE bit in the serial control register (SCR) to halt the transmit/receive
[3] Write 0 to the CKE0 bit in SCR to halt the clock.
[4] Wait for one serial clock period.
[5] Write H'00 to SMR and SCMR.
[6] Make the transition to the software standby state.
• When returning to smart card interface mode from software standby mode
[7] Exit the software standby state.
[8] Set the CKE1 bit in SCR to the value for the fixed output state (current SCK pin state) when
[9] Set smart card interface mode and output the clock. Signal generation is started with the
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REJ09B0220-0600
the value for the fixed output state in software standby mode.
operation. At the same time, set the CKE1 bit to the value for the fixed output state in software
standby mode.
During this interval, clock output is fixed at the specified level, with the duty preserved.
software standby mode is initiated.
normal duty.
Operation in GSM Mode
[1] [2] [3]
Normal operation
Figure 15.9 Clock Halt and Restart Procedure
[4] [5]
[6]
Software
standby
[7]
[8] [9]
Normal operation