AT88SC3216C

11

5014KS–SMEM–08/09

8.

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.

9.

Protocol Selection

The AT88SC3216C supports two different communication protocols.

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.

The power-up sequence determines which of the two communication protocols will be used.

9.1.

Asynchronous T = 0 Protocol

This power-up sequence complies with ISO 7816-3 for a cold reset in smart card applications.

• Set I/O-SDA in receive mode.

• Provide a clock signal to CLK-SCL.

• RST goes high after 400 clock cycles.

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.

Asynchronous T = 0 Protocol (Gemplus Patent)

Vcc

I/O-SDA

RST

CLK-SCL

ATR

After a successful ATR, the Protocol and Parameter Selection (PPS) protocol, as defined by ISO 7816-3, may be used

to negotiate the communications speed with CryptoMemory devices 32 Kbits and larger. CryptoMemory supports D

values of 1, 2, 4, 8, 12, and 16 for an F value of 372. Also supported are D values of 8 and 16 for F = 512. This allows

selection of 8 communications speeds ranging from 9600 baud to 153,600 baud.