D12320VF25V Datasheet, PDF (560/1146 Pages) Renesas Technology Corp – Old Company Name in Catalogs and Other Documents

Section 13 Smart Card Interface
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.
13.3.8 Operation in Block Transfer Mode
Operation in block transfer mode is the same as in SCI asynchronous mode, except for the
following points. For details, see section 12.3.2, Operation in Asynchronous Mode.
Data Format: The data format is 8 bits with parity. There is no stop bit, but there is a guard time
of 2 or more bits (1 or more bits in reception).
Also, except during transmission (with start bit, data bits, and parity bit), the transmission pins go
to the high-impedance state, so the signal lines must be fixed high with a pull-up resistor.
Transmit/Receive Clock: Only an internal clock generated by the built-in baud rate generator can
be used as the transmit/receive clock. The number of basic clock periods in a 1-bit transfer interval
can be set to 32, 64, 372, or 256 with bits BCP1 and BCP0. For details, see section 13.3.5, Clock.
ERS (FER) Flag: As with the normal smart card interface, the ERS flag indicates the error signal
status, but since error signal transmission and reception is not performed, this flag is always
cleared to 0.
13.4 Usage Notes
The following points should be noted when using the SCI as a smart card interface.
Receive Data Sampling Timing and Receive Margin in Smart Card Interface Mode: In smart
card interface mode, the SCI operates on a base clock with a frequency of 32, 64, 372, or 256
times the transfer rate (determined by bits BCP1 and BCP0).
In reception, the SCI samples the falling edge of the start bit using the base clock, and performs
internal synchronization. Receive data is latched internally at the rising edge of the 16th, 32nd,
186th, or 128th pulse of the base clock. Use of a 372-times clock is illustrated in figure 13.10.
Rev.7.00 Feb. 14, 2007 page 526 of 1108
REJ09B0089-0700