EM78P451S

`Operating voltage range: 2.3V~5.5V.
`Operating temperature range: 0°C~70°C.
`Operating frequency range (base on 2 clocks ):
  * Crystal mode: DC~20MHz at 5V, DC~8MHz at 3V, DC~4MHz at 2.3V.
  * RC mode: DC~4MHz at 5V, DC~4MHz at 3V, DC~4MHz at 2.3V.
`Low power consumption:
  * Less then 3 mA at 5V/4MHz
  * Typically 10 A during sleep mode
`Serial Peripheral Interface (SPI) available.
`4K * 13 bits on chip ROM (EM78P451S).
`11 special function registers.
`140* 8 bits on chip general-purposed registers.
`5 bi-directional I/O ports (35 I/O pins).
`3 LED direct sinking pins with internal serial resistors.
`Built-in RC oscillator with external serial resistor, ±10% variation.
`Built-in power-on reset.
`5 stacks for subroutine nesting.
`8-bit real time clock/counter (TCC) with overflow interrupt.
`Two machine clocks or four machine clocks per instruction cycle.
`Power down mode.
`Programmable wake up from sleep circuit on I/O ports.
`Programmable free running on-chip watchdog timer.
`12 wake-up pins.
`2 open-drain pins.
`2 R-option pins.
`32 programmable pull-high input pins.
`Packages:
  * 40 pin DIP 600mil : EM78P451SP .
  * 40 pin SOP 450mil : EM78P451SWM
  * 44 pin QFP : EM78P451SAQ.
`Four types of interrupts.
  * External interrupt (/INT).
  * SPI transmission completed interrupt.
  * TCC overflow interrupt.
  *  Timer1 comparator match interrupt.

The EM78P451S is an 8-bit microprocessor designed and developed with low-power, high speed CMOS technology. Its operational kernel is implemented with RISC-like architecture and is available in the mask ROM version. The one time programmable (OTP) version is flexible, both in mass production or engineering test stages. OTP provide users with unlimited volume with favorable price opportunities. This device is equipped with the Serial Peripheral Interface (SPI) function. The EM78P451S is very suitable for wired communication. Only 58 easy-to-learn instructions are needed and user's program can be emulated with EMC In-Circuit Emulator (ICE).