EM78870
8-bit Micro-controller
I.General Description
The EM78870 is an 8-bit RISC type microprocessor with low power, high speed CMOS technology.
Integrated onto a single chip are on_chip watchdog (WDT), RAM, ROM, programmable real time clock /counter,
internal interrupt, power down mode, LCD driver, build-in KEY TONE clock generation, Programming Tone generators,
Serial Peripheral Interface(SPI), comparator and tri-state I/O. The EM78870 provides a single chip solution to design a
message_display.
II.Feature
CPU
•Operating voltage range : 2.2V~5.5V(Normal mode), 2.0V~5.5V(Green mode)
•32K× 13 on chip Program ROM
•2.5K× 8 on chip data RAM
•144 byte working register
•Up to 51 bi-directional tri-state I/O ports (32 shared with LCD Segment pins)
•IO with internal Pull high, wake-up and interrupt functions
•STACK: 32 level stack for subroutine nesting
•TCC: 8-bit real time clock/counter (TCC) with 8-bit prescaler
•COUNTER1: 8-bit counter with 8-bit prescaler can be an interrupt source
•COUNTER2: 8-bit counter with 8-bit prescaler can be an interrupt source
•Watch Dog : Programmable free running on chip watchdog timer
•CPU modes:
Mode
CPU status
Main clock
32.768kHz clock status
Sleep mode Turn off
Turn off
Turn off
Idle mode
Turn off
Turn off
Turn on
Green mode Turn on
Turn off
Turn on
Normal mode Turn on
Turn on
Turn on
•12 interrupt source : 8 external , 4 internal
•Key Scan : Port key scan function up to 16x4 keys
•Sub-Clock: 32.768kHz crystal
•Main-clock: 3.5826MHz multiplied by 0.25, 0.5, 1 or 3 generated by internal PLL
•Key tone output (shared with IO) : 4kHz, 2kHz, 1kHz
•Comparator: 3-channel comparators, internal (16 level) or external reference voltage (shared with IO)
•Serial Peripheral Interface (SPI) : Interrupt flag available for the read buffer full, Programmable baud rates of
communication, Three-wire synchronous communication. (shared with IO)
Programmable Tone Generators
•Operation Voltage 2.2V〜5.5V
•Programmable Tone1 and Tone2 generators
•Independent single tone generation for Tone1 and Tone2
•Mixed dual tone generation by Tone1 and Tone2 with 2dB difference
LCD (8x80, 9x80, 16x80, 24x72)
•Maximum common driver pins : 16/24
•Maximum segment driver pins : 80(SEG0..SEG79)/72(SEG8..SEG79)
•Shared COM16 ~ COM23 pins with SEG0 ~ SEG7 pins
•1/4 bias for 8, 9 and 16 common mode and 1/5 bias for 24 common mode
•1/8, 1/9, 1/16, 1/24 duty
•16 Level LCD contrast control (software)
•Internal resistor circuit for LCD bias
•Internal voltage follower for better display
Package type
•128-pin QFP or chip : EM78870AQ (POVD disable), EM78870BQ (POVD enable), EM78870H
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* This specification are subject to be changed without notice.
1
2001/08/29