HD6412240 RENESAS [Renesas Technology Corp], HD6412240 Datasheet - Page 540

• Manufacturer Part Number: HD6412240
• Description: Renesas 16-Bit Single-Chip Microcomputer H8S Family / H8S/2200 Series
• Manufacturer: RENESAS [Renesas Technology Corp]

Section 13 Smart Card Interface
Software
standby
Normal operation
Normal operation
[1] [2] [3]
[4] [5] [6]
[7] [8] [9]
Figure 13.9 Clock Halt and Restart Procedure
Powering On
To secure the clock duty 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.
13.4
Usage Notes
The following points should be noted when using the SCI as a Smart Card interface.
Receive Data Sampling Timing and Reception Margin in Smart Card Interface Mode
In Smart Card Interface mode, the SCI operates on a basic clock with a frequency of 372 times the
transfer rate.
In reception, the SCI samples the falling edge of the start bit using the basic clock, and performs
internal synchronization. Receive data is latched internally at the rising edge of the 186th pulse of
the basic clock. This is illustrated in figure 13.10.
Rev.3.00 Mar. 26, 2007 Page 498 of 772
REJ09B0355-0300