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