ST23YS08 is a smart card MCU with enhanced security and 8 KBytes high-density EEPROM. It is primarily used in the banking sector, targeting VISA and CAST certificates. The hardware features include an enhanced 8/16-bit CPU core, 16 MBytes linear addressable memory, 108 Kbytes user ROM, 2 Kbytes user RAM, 8 Kbytes user EEPROM, and more.