The W78L54 microcontroller supplies a wider frequency and supply voltage range than most 8-bit
microcontrollers on the market. It is compatible with the industry standard 80C54 microcontroller
series. The W78L54 contains four 8-bit bidirectional parallel ports, one extra 4-bit bit-addressable I/O
port (Port 4) and two additional external interrupts ( INT2 , INT3 ), three 16-bit timer/counters, one
watchdog timer and a serial port. These peripherals are supported by a eight-source, two-level
interrupt capability. There are 256 bytes of RAM and an 16K byte mask ROM for application
The W78L54 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
• Fully static design
• Supply voltage of 1.8V to 5.5V
• DC-24 MHz operation
• 256 bytes of on-chip scratchpad RAM
• 16K bytes of on-chip mask ROM
• 64K bytes program memory address space
• 64K bytes data memory address space
• Four 8-bit bidirectional ports
• Three 16-bit timer/counters
• One full duplex serial port
• Eight-source, two-level interrupt capability
• One extra 4-bit bit-addressable I/O port
• Two additional external interrupts INT2 / INT3
• Watchdog timer
• EMI reduction mode
• Built-in power management
• Code protection
• Packages:
− DIP 40: W78L54-24
− PLCC 44: W78L54P-24
− QFP 44: W78L54F-24
Publication Release Date: Sep. 1998
Revision A0