AT88SC0404C_09 ATMEL [ATMEL Corporation], AT88SC0404C_09 Datasheet - Page 10

• Manufacturer Part Number: AT88SC0404C_09
• Description: CryptoMemory 4 Kbit
• Manufacturer: ATMEL [ATMEL Corporation]

8.
9.
9.1.
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Security Fuses
There are three fuses on the device that must be blown during the device personalization process. Each fuse locks
certain portions of the configuration memory as OTP memory. Fuses are designed for the module manufacturer, card
manufacturer and card issuer and should be blown in sequence, although all programming of the device and blowing of
the fuses may be performed at one final step.
Protocol selection
The AT88SC0404C supports two different communication protocols.
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The power-up sequence determines which of the two communication protocols will be used.
Asynchronous T = 0 Protocol
This power-up sequence complies with ISO 7816-3 for a cold reset in smart card applications.
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The device will respond with a 64-bit ATR code, including historical bytes to indicate the memory density within the
CryptoMemory family. Once the asynchronous mode has been selected, it is not possible to switch to the synchronous
mode without powering off the device.
Figure 10.
AT88SC0404C
CLK-SCL
I/O-SDA
Smart Card Applications: The asynchronous T = 0 protocol defined by ISO 7816-3 is used for compatibility with
the industry’s standard smart card readers.
Embedded Applications: A 2-wire serial interface is used for fast and efficient communication with logic or
controllers.
V
Set I/O-SDA in receive mode.
Provide a clock signal to CLK-SCL.
RST goes high after 400 clock cycles.
CC
RST
V cc
goes high; RST, I/O-SDA and CLK-SCL are low.
Asynchronous T = 0 Protocol (Gemplus Patent)
ATR
2023KS–SMEM–10/09