The X46402 combines several functions into one device. The first is a dual voltage CPU supervisor plus 64Kbit serial EEPROM memory with password protected write and read operations. The size of the password protected area is selectable by 3 control bits. A Write Protect (WP) pin in conjunction with a WPEN bit provides hardware OTP control of the configuration of the array. Password protected areas require 64 bit read or write passwords prior to access. The eighth illegal password entry (regardless of the number of correct entries) sets an OTP tamper bit. This bit is one of the 32 bits in the Device ID. A secondary voltage monitor circuit activates a V2FAIL pin when the secondary supply voltage drops below a V2trip voltage. This circuit is primarily intended to detect the immediate loss of the battery supply. A low Vcc voltage detect circuit activates a RESET pin when Vcc drops below a VTRIP voltage. This signal also blocks read or write operations. A watchdog timer with the time period controlled by three bits provides several possible time out periods from 150ms to 1 minute.