M34551E8-XXXFP

` Minimum instruction execution time ...................................1.5 ms
    (f(XIN)=8.0 MHz, VDD=5.0 V, system clock = f(XIN)/4)
`Supply voltage
                      .................... 2.5 V to 5.5 V (One Time PROM version)
                        ............................2.2 V to 5.5 V (Mask ROM version)
`System clock switch function ..... Clock divided by 4 or not divided
` LCD control circuit
   Segment output .........................................................................20
   Common output ...........................................................................4
` Carrier wave frequency switch function System clock, system clock/2, system clock/8, system clock/12, system clock/16, system clock/24, "H" fixed
` Timers
    Timer 1 ........................................ 8-bit timer with a reload register
    Timer 2 ........................14-bit timer also used as a watchdog timer
    Timer LC ..................................... 4-bit timer with a reload register
` Interrupt .........................................................................3 sources
` Voltage drop detection circuit ......................................................1
` Clock generating circuit (ceramic resonance and quartz-crystal oscillation)

The 4551 Group is a 4-bit single-chip microcomputer designed with CMOS technology. Its CPU is that of the 4500 series using a simple, high-speed instruction set. The computer of 4551 is equipped with an 8-bit timer with a reload register, a 14-bit timer which is also used as a watchdog timer, a 4-bit timer with a reload register, a carrier wave output circuit and an LCD control circuit.

The mask ROM version and built-in PROM version of 4551 Group are produced as shown in the table below.