GENERAL DESCRIPTION
The W78E058B is an 8-bit microcontroller which has an in-system programmable Flash EPROM for firmware updating. The instruction set of the W78E058B is fully compatible with the standard 8052. The W78E058B 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 W78E058B allows the program memory to be programmed and read electronically. Once the code is confirmed, the user can protect the code for security.
The W78E058B microcontroller has two power reduction modes, idle mode and power-down mode, both of which are software selectable. The idle mode turns off the processor clock but allows for continued peripheral operation. The power-down mode stops the crystal oscillator for minimum power consumption. The external clock can be stopped at any time and in any state without affecting the processor.

FEATURES
● Fully static design 8-bit CMOS microcontroller
● 32K bytes of in-system programmable Flash EPROM for Application Program (APROM)
● 4K bytes of auxiliary ROM for Loader Program (LDROM)
● 512 bytes of on-chip RAM (including 256 bytes of AUX-RAM, software selectable)
● 64K bytes program memory address space and 64K bytes data memory address space
● Four 8-bit bi-directional ports
● One 4-bit multipurpose programmable port
● Three 16-bit timer/counters
● One full duplex serial port
● Eight-sources, two-level interrupt capability
● Built-in power management
● Code protection
● Packaged in
   − Lead Free (RoHS) DIP 40: W78E058B40DL
   − Lead Free (RoHS) PLCC 44: W78E058B40PL
   − Lead Free (RoHS) PQFP 44: W78E058B40FL