5.0. Smart Card Interface
The interface between the ACR101 (CCID) and the inserted smart card follows the specifications of
ISO7816-3.
5.1. Smart Card Power Supply VCC (C1)
The current consumption of the inserted card must not be higher than 50mA.
5.2. Programming Voltage VPP (C6)
According to ISO 7816-3, the smart card contact C6 (VPP) supplies the programming voltage to the
smart card. Since all common smart cards in the market are EEPROM based and do not require the
provision of an external programming voltage, the contact C6 (VPP) has been implemented as a
normal control signal in the ACR101 (CCID). The electrical specifications of this contact are identical
to those of the signal RST (at contact C2).
5.3. Card Type Selection
The controlling PC has to select the card type always, through the proper command sent to the
ACR101 (CCID) prior to activating the inserted card. This includes both the memory cards and MCU-
based cards. For MCU-based cards the reader allows to select the preferred protocol, T=0 or T=1.
However, this selection is only accepted and carried out by the reader through the PPS when the card
inserted in the reader supports both protocol types. Whenever an MCU-based card supports only one
protocol type, T=0 or T=1, the reader automatically uses that protocol type, regardless of the protocol
type selected by the application.
5.4. Interface for Microcontroller-Based Cards
For microcontroller-based smart cards, only the contacts C1 (VCC), C2 (RST), C3 (CLK), C5 (GND)
and C7 (I/O) are used. A frequency of 4 MHz is applied to the CLK signal (C3).
5.5. Card Tearing Protection
The ACR101 (CCID) provides a mechanism to protect the inserted card when it is suddenly withdrawn
while it is powered up. The power supply to the card and the signal lines between the ACR101 (CCID)
and the card are immediately deactivated when the card is being removed. As a general rule,
however, to avoid any electrical damage,
a card should only be removed from the reader while it
is powered down.
Note:
The ACR101 (CCID) never switches on the power supply to the inserted card by itself.
This must be done by the controlling computer through the proper command sent to the reader.
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ACR101 PC/SC Memory Card Access
Version 1.0
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