¡ Semiconductor

MSM6882-3/6882-5

4/15

PIN DESCRIPTION

Name

Description

Crystal connection pins.

A 3.6864 MHz or 7.3728 MHz crystal shall be connected.

When an external clock is applied for MSM6882's oscillation source, it has to be input to X2.

In this case, X2 has to be AC-coupled by the capacitor of 200 pF. X1 shall be left open.

X1

Master clock selection.

MCS

Modulator enable.

When a "high" is input on this pin, MSK modulator output is connected to the input of transmit

LPF.

When a "low" is input on this pin, TI is connected to the input of transmit LPF.

ME

Send data input.

The data on this pin is synchronized with the rising edge of ST and input to MSK modulator

as an actual transmit data.

MSK Modulated Data

SD

ST

SD

This timing signal is used to latch serial input data on the SD pin.

The frequency of ST coincides with the transmission bit rate.

ST

Modulation method selection.

Data put on this pin selects either SINE FAST FSK or COSINE FAST FSK.

Data (2400 bps)

Sine Fast FSK

Cosine Fast FSK

010

0

1

1

SIN

X2

MCS

Crystal or External Clock

0

3.6864 MHz

1

7.3728 MHz

Preamble or data transmission selection.

When a "low" is input on this pin, the data put on the SD pin is output on the AO pin.

When a "high" is input on this pin, the data put on the SD pin is neglected and preamble data

is output.

Data put on PRE is latched on the rising edge of ST.

Preamble means to modulate as 010101...pattern.

PRE