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