AT88SC0104CA View Datasheet(PDF) - Atmel Corporation
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MFG CO.
'AT88SC0104CA' PDF : 20 Pages View PDF
AT88SC0104CA
13. Protocol Selection
The AT88SC0104CA supports two different communication protocols.
Smartcard Applications:
Smartcard applications use ISO 7816-B protocol in asynchronous T = 0 mode for compatibility and
interoperability with industry standard smartcard readers.
Embedded Applications:
A 2-wire serial interface provides fast and efficient connectivity with other logic devices or microcontrollers.
The power-up sequence determines establishes the communication protocol for use within that power cycle. Protocol
selection is allowed only during power-up.
13.2.
Synchronous 2-Wire Serial Interface
The synchronous mode is the default mode after power up. This is due to the presence of an internal pull-up on RST.
For embedded applications using CryptoMemory in standard plastic packages, this is the only available communication
protocol.
Power-up VCC, RST goes high also.
After stable VCC, SCL(CLK) and SDA(I/O) may be driven.
Once synchronous mode has been selected, it is not possible to switch to asynchronous mode without first
powering off the device
Figure 13. Synchronous 2-Wire Protocol
Vcc
I/O-SDA
RST
CLK-SCL
1 2345
Note: Five clock pulses must be sent before the first command is issued.
15
5200ES–CRYPT–08/09
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