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12.3
Operation
12.3.1
Overview
The main functions of the Smart Card interface are as follows.
• One frame consists of 8-bit and plus a parity bit.
• In transmission, a guard time of at least 2 etu (Elementary Time Unit: the time for transfer of
one bit) is left between the end of the parity bit and the start of the next frame.
• If a parity error is detected during reception, a low error signal level is output for one etu
period, 10.5 etu after the start bit.
• If the error signal is sampled during transmission, the same data is transmitted automatically
after the elapse of 2 etu or longer.
• Only asynchronous communication is supported; there is no clocked synchronous
communication function.
12.3.2
Pin Connections
Figure 12-2 shows a schematic diagram of Smart Card interface related pin connections.
In communication with an IC card, since both transmission and reception are carried out on a
single data transmission line, the TxD
The data transmission line should be pulled up to the V
When the clock generated on the Smart Card interface is used by an IC card, the SCK
is input to the CLK pin of the IC card. No connection is needed if the IC card uses an internal
clock.
LSI port output is used as the reset signal.
Other pins must normally be connected to the power supply or ground.
394
pin and RxD
pin should be connected with the LSI pin.
0
0
CC
power supply with a resistor.
pin output
0
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