General Description

The EM78808 is an 8-bit CID (Call Identification) RISC type microprocessor with low power, high speed CMOS technology. Integrated onto a single chip are on chip watchdog (WDT), RAM, program ROM, data ROM, programmable real time clock/counter, external/internal interrupt, power down mode, LCD driver, FSK decoder, Call waiting decoder, Energy Detector (DED) , DTMF receiver, Programming Tone generator, build-in KEY TONE clock generation, Comparator and tri-state I/O. The EM78808 provides a single chip solution to design a CID of calling 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

256K×8 on chip data ROM (2.5V ~ 5.5V for main clock 3.5826MHz)

8K×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

13 interrupt source , 8 external , 5 internal

Key Scan : Port key scan function up to 16x4 keys

Sub-Clock: 32.768KHz crystal

Main-clock: 3.5862MHz multiplied by 0.25, 0.5, 1 or 3 generated by internal PLL

Key tone output :4KHz, 2KHz ,1KHz (shared with IO)

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)

An OP inside (shared with IO)

► Current D/A

Operation Voltage : 2.5V∼5.5V

7-bit resolution and 3-bit output level control

Current DA output can drive speaker through a transistor for sound playing. (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

Can be programmed for DTMF tone generation

Can be programmed for FSK signal (Bell202 or V.23) generation

►CID

Operation Voltage 2.7V∼5.5V for FSK

Operation Voltage 2.7V∼5.5V for DTMF receiver

Compatible with Bellcore GR-30-CORE (formerly as TR-NWT-000030)

Compatible with British Telecom (BT) SIN227 & SIN242

FSK demodulator for Bell 202 and ITU-T V.23 (formerly as CCITT V.23)

Differential Energy Detector (DED) for line energy detection

► CALL WAITING

Operation Voltage 2.6V∼5.5V

Compatible with Bellcore special report SR-TSV-002476

Call-Waiting (2130Hz plus 2750Hz) Alert Signal Detector

Good talkdown and talkoff performance

Sensitivity compensated by adjusting input OP gain

► 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

136 pin Chip : EM78808BH

128 pin QFP : (EM78808AAQ , POVD disable) (EM78808ABQ , POVD enable)

128 pin QFP : (EM78808BAQ , POVD disable) (EM78808BBQ , POVD enable)

Application

1. adjunct units

2. answering machines

3. feature phones