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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