FEBL7731-02-02
1
Semiconductor
User’s Manual for
MSM7731-02 Evaluation Board
- 2 -
1.9
Variable Resistors
There are 4 variable resistors located on the right lower side of the evaluation board. The function of each
resistor is as follows:
RV1: MIC (Microphone) level adjustment
RV2: MIN (Line input) level adjustment
RV4: SP (Speaker output) level adjustment
RV5: MOUT (Line out) level adjustment
1.10
On-board Microcontroller Interface Operation
Besides the Pin Control Mode operation, this board can evaluate the MSM7731-02 by using on-board
registers as well as an external microcontroller. The on-board register can easily be set by using toggle
switches on the PCB (MCU Interface Mode).
1.11
Spare Area for Additional Amplifier
The amplifier such as for the line out to an external telephone handset can be used as an option by using
the area of U15.
1.12
LED Indicator
On-board LEDs are used for the confirmation of the register contents.
1.13
On-board Crystal
The 19.2 MHz crystal is equipped on the board. An oscillator can be used as an option by using the socket
of XL2 (the oscillator is not included in this kit).
1.14
Measurement Location for External Oscilloscope
During the tuning process, some of the output pins of the MSM7731-02 have to be measured by using an
external oscilloscope. There are 6 points where the pins of the oscilloscope have to be set.
(1)
AVFRO: Right lead of R13 resistor
(See the Board Schematic of this user manual)
(2)
AGSX: Left lead of R9 resistor
(See the Board Schematic of this user manual)
(3)
Pin 8 of LM4861: (See the Board Schematic of this user manual)
(4)
LVFRO: Left lead of R20 resistor
(See the Board Schematic of this user manual)
(5)
LGSX: Right lead of R12 resistor
(See the Board Schematic of this user manual)
(6)
LOUT: Left lead of R21 resistor
(See the Board Schematic of this user manual)
