256 Bytes Secured Memory Smart Card

タイトルまたは説明

**6 Bytes Secured Memory Smartcard Description MM*3SC***2 contains **6 x 8 bits of EEPROM main memory and a *2 x 1 bit protection PROM memory. The main memory can be randomly accessed byte by byte. During memory erase, all 8 bits of a byte are set to logical one. During memory write, individual bit(s) are set to logical zeros depend on the data value to be written. Normally, a data change may consists of an erase and then write operation. The write or erase operation takes at least 2.5ms to complete. The first *2 bytes (Address: 0 to *1) in memory are irreversibly protected by the corresponding *2 protect bits in the *2 x 1 bit protection memory. The *2 protect bits are one-time programmable and cannot be erased once they are set to logical zero. MM*3SC***2 also provides a *-bit Error Counter (EC) and three bytes Programmable Security Code (PSC) to prevent unauthorized erase/ write operation to the memory. All the memory, except the PSC can be read after the chip is powered on. But, the memory can be written or erased only after the PSC is entered and verified correct. After three successive unsuccessful verifications of PSC, the Error Counter lock the chip from further attempt, and hence the memory can never be erased or written.