1K Bytes Secure Memory Smart Card

Product Description

8K Bytes Secure Memory Smart Card DESCRIPTION MM*3SC***8 contains ***4 x 8 bits of EEPROM with programmable write protection for each byte. Random read access to any byte in the memory is not possible except to certain areas of the memory. The memory can also be erased and written byte by byte. Erasing old data in the byte location must be performed before new data can be written to the new location. Each byte in the memory has a corresponding protect bit. The protect bits are only one time programmable and cannot be erased. After the protect bits are enabled (logic 0), the corresponding bytes can never be changed again. A write-protect bit with data-compare function is available for user to verify the data in the memory before enabling the protect bit. MM*3SC***8 offers two bytes of Programmable Security Code (PSC) against unauthorized memory read and write/erase operations. The entire memory array except the first *4 bytes addresses (**0H**3FH) and the bottom *6 bytes addresses (3F0H*3FFH) is unreadable. Refer to Figure 1A. The memory can be read, written or erased only after PSC verification. If the user fails to enter the correct PSC in eight consecutive attempts, the device will block any further PSC entry attempts and the memory can never be read, erased or written again. The PSC bytes are pre-programmed by the manufacturer with a code, which is specified for customer for device transport security purposes, before the device are shipped to the customer. The Error Counter will be pre-erased by the manufacturer to allow maximum attempts (maximum of eight) for PSC entry.