MSM7564-01 데이터 시트보기 (PDF) - Oki Electric Industry

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MSM7564-01

A Single Chip 14.4 kbps Data & Fax Modem

Oki Electric Industry 

¡ Semiconductor

MSM7564-01

Serial Interface

MSM7564 provides a one channel serial interface, including synchronous-asynchronous and

asynchronous-synchronous converters. Select synchronous or asynchronous. In synchronous mode,

the transmit data is synchronized with the clock provided from this chip or DTE. Serial transmit data

to STD pin is latched with the rising edge of ST1 or ST2, and receive data on SRD is output

synchronously with the falling edge of RT. This chip also includes a scrambler and descrambler.

Parallel Interface

MSM7564 contains twenty 8-bit registers (location from addresses 00H through 0FH and 1C through

1F), which are used to control this chip and to detect various signals. Connect this chip to either

multiplexed address and data bus such as Intel-compatible (80 mode) or separate address and data

bus such as Motorola-compatible (68 mode).

Transmit and Receive Level

Analog input and output are differential amplifiers, and are ±1.2 VO-P peak signals. The level of the

transmit line signal is –10 dBm. The modem can provide 15 dB programmable transmit attenuation

with 1 dB steps controlled by the TXLEV bit in located 0BH register. Receive signal level is from –10

dBm to –43 dBm. Carrier detection level can be selected from 4 levels (–43, –33, –26, –16 dBm) by the

CDLEV bit located in register 0BH. An amplitude equalizer in transmitter and receiver can be

individually controlled by RAEQL and SAEQL bits in register 07H.

DTMF Tone, Answer Tone, and Guard Tone Generators

The modem can generate 16 types of DTMF tones using the PBANSEL bit located in register 05H.

It also generates answer tone and guard tone.

Various Detection Circuits

The internal detection circuit monitors carrier, call progress tone, answer tone, DTMF tone, and other

receive signals needed for each modem mode, and stores them in the corresponding bits of each of

the following registers : 0C, 0D, 1C, and 1D. Classification of detected tones is controlled by

DETMODE bit in register 08H. If the contents of registers 0C, 0D, 1C, and 1D change, the interruption

signal (STCHG) for controlling microprocessor is generated.

Programmable Tone Generator and Detector

The transmission of programmable tone 1 and tone 2 is available and is controlled by PTONE1 and

PTONE2 bits in 05H register. To use this function, the initial download of frequency and gain is

needed. This modem can output 16 kinds of frequency selected by PBANSEL bit of register 05H

(composition of two tones is also available.). PTONE1 and PTONE2 are the same frequency and only

the gain is variable. Each bit of D7, D6, D3, D2, D1, and D0 in register 0C can be used for

programmable tone detecting by rewriting a coefficient of internal filter at the initial download.

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