msm6895 Oki Semiconductor, msm6895 Datasheet - Page 7

• Manufacturer Part Number: msm6895
• Description: Multi-function Pcm Codec
• Manufacturer: Oki Semiconductor

¡ Semiconductor
MSM6895/6896
SA0, SA1
Sounder (ringing tone) driving outputs.
The output signal on SA1 is inverted against the signal on SA0. The sounder circuit can be easily
configured by connecting a piezo-sounder between SA0 and SA1. Through processor control, the
ringing tone volume is selectable from four levels and one of six tone combinations is selectable.
Initially, the ringing tone volume is set at a maximum and the tone combination is set externally.
If these pins are used with no-load, tone volume cannot be controlled.
When tone volume control is required, a load resistor must be connected between SA0 and SA1.
RMI, RMO0, RMO1
Receive main amplifier input and outputs.
RMI is the main amplifier input and RMO0 and RMO1 are the main amplifier outputs. The
output signal on RMO1 is inverted against RMO0, so the earphone of a piezo electric-type
handset is directly connected between RMO0 and RMO1. The RMI input pin is connected to the
receive preamplifier output pin (RPO).
If the adjusting of receive path frequency characteristics is required, insert the following circuit
for adjustment. During initial setting, the speech path from RMI to RMO0 and RMO1 is
disconnected and the output of RMO0 and RMO1 is at the VSG level (VA/2). The speech path
is provided by processor control.
A circuit example for adjustment of frequency characteristics
RPO
RMI
VSG
C2
R1
R2
C1
SPO
Output of preamplifier for speaker.
Since the driving capability is 2.4 V
for the load of 20 kW, SPO can not directly drive a speaker.
PP
During initial setting, SPO is in a non-signal state (VSG level), and a speech signal, RTONE0,
RTONE1, FTONE, hold acknowledge tone, and PB signal acknowledge tone are output through
processor control.
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