The W78E58B is an 8-bit microcontroller which has an in-system progRAMmable Flash EPROM for
firmware updating. The instruction set of the W78E58B is fully compatible with the standard 8052. The
W78E58B contains a 32K bytes of main ROM and a 4K bytes of auxiliary ROM which allows the
contents of the 32KB main ROM to be updated by the loader progRAM located at the 4KB auxiliary
ROM 512 bytes of on-chip RAM four 8-bit bi-directional and bit-addressable I/O ports an additional 4-
bit port P4 three 16-bit timer/counters a serial port. These peripherals are supported by a eight
sources two-level interrupt capability. To facilitate progRAMming and verification, the ROM inside the
W78E58B allows the progRAM memory to be progRAMmed and read electronically. Once the code is
confirmed, the user can protect the code for security
