HD6432621 Hitachi, HD6432621 Datasheet - Page 557

• Manufacturer Part Number: HD6432621
• Description: (HD64F262x Series) 16-Bit Microcomputer
• Manufacturer: Hitachi

Note: For block transfer mode, see section 13.4, SCI Interrupts.
14.3.7
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 transmit/receive
[3] Write 0 to the CKE0 bit in SCR to halt the clock.
[4] Wait for one serial clock period.
[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
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.
normal duty.
Operation in GSM Mode
[1] [2] [3]
Normal operation
Figure 14-9 Clock Halt and Restart Procedure
[4] [5]
Software
standby
[6] [7]
Normal operation
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