General Description
The EM78862C is an 8-bit RISC type microprocessor with low power, high speed CMOS technology. Integrated into the single chip are built-in watchdog (WDT), RAM, ROM, programmable real-time clock/counter, internal interrupt, power-down mode, LCD driver, and bi-directional I/O. The EM78862C provides a single chip solution for scientific calculator design applications.

FEATUREs
CPU
„ Operating voltage range: 2.2V ~ 3.6V
„ 16K x 13 on-chip ROM
„ 1.25K x 8 on-chip RAM
„ 144 byte working register
„ Up to 24 bi-directional I/O ports (16 shared with LCD segment pins)
„ 8 level stack for subroutine nesting
„ 8-bit real time clock/counter (TCC) can be configured as interrupt sources with prescaler
„ Two sets of 8 bit counters are set asinterrupt sources with prescaler
„ Programmable free running on-chip watchdog timer
„ Four modes (internal PLL clock 3.579MHz)
   •  SLEEP Mode: CPU and 3.579MHz clock turn off, 32.768kHz clock turn off
   •  IDLE Mode: CPU and 3.579MHz clock turn off, 32.768kHz clock turn on
   •  GREEN Mode: 3.579MHz clock turn off, CPU and 32.768kHz clock turn on
   •  NORMAL Mode: 3.579MHz clock turn on, CPU and 32.768kHz clock turn on
„ Input port wake up function
„ Six interrupt sources: three internal, three external
   •  Internal:
      1. TCIF for TCC timer overflow interrupt
      2. CNT1 for COUNTER 1 overflow interrupt
      3. CNT2 for COUNTER 2 overflow interrupt
  •  External:
     1. INT 0 for Port 70, Port 71, Port 72, or Port 73, has a falling edge trigger interrupt
     2. INT 1 for Port 74, Port 75, or Port 76, has a falling edge trigger interrupt
     3. INT 3 for Port 77 has a rising edge or falling edge trigger (by CONT register) interrupt
„ 67-pin die chip (EM78862CH)
„ Port key scan function
„ Clock frequency 32.768kHz or RC mode
LCD
„ LCD operation voltage:4.5 V ( VDD must be fixed at 3V )
„ Common driver pins:16
„ Segment driver pins:32
„ 1/4 bias
„ 1/16 duty

 Applications
„ Data Bank
„ Message display box
„ Scientific calculator