REV. A

–14–

SSM2160

that is assigned to the connector used on your PC if different

from the default LPT1.

Windows Control Panel

The control panel contains all the functions required to control

the SSM2160, and each feature is described below. A mouse is

needed to operate the various controls. It is possible to overload

the VCA by incorrect input levels and master and control settings.

If you have not read the sections of the data sheet regarding

control planning, do so now. While no damage will occur to

the SSM2160, the results will be unpredictable.

Master Volume

The master volume fader controls the 7-bit word that deter-

mines the attenuation level. There are 128 levels (2

from 0 dB attenuation to –127 dB attenuation. To change the

level, simply click the up or down arrows or click in the space

directly above or below the fader knob, or drag the knob up or

down to its desired position. (Drag refers to placing the screen

cursor arrowhead on the control, pressing and holding the left

mouse button while moving the arrow to the desired position.)

Master Mute

Below the master volume fader is the Master Mute button. Click

this button to mute all channels. Clicking it again will unmute all

channels. The application defaults to Mute when started. Mute

reduces outputs to approximately –95 dB below inputs up to 0 dBu.

Channel Volume

Each of the channel fader controls can be set to one of 32 levels

of gain, from 0 dB to 31 dB. See the previous section on Master

Volume for details.

Channel Mute

Same function as Master Mute but on a channel basis. Due to

the design limitations, muting an individual channel results in

an increased distortion level of the unmuted channels. Users must

determine if this condition is acceptable in their application.

Channel Balance

The channel balance fader adjusts all channels over their range

without affecting the master volume setting. Relative channel

differences will be maintained until the top or the bottom of

the range is reached. The master volume fader does the same

function as this fader, which was made available for evaluation

convenience.

Master and Channel Fades

Both master and channel fades can be achieved by pressing the

MEM 1 button when levels are at a desired starting position and

the MEM 2 button at the desired ending position. Fade controls

individual channels, and Master Fade controls the master volume.

Fade Time sets timing from 0.1 (fastest) to 9.9 (slowest). Press

Fade to commence operation. If Fade is pressed again, a fade

back to the starting point will occur. The Jump button causes a

direct jump to the opposite memory position.

Halt

Halt is a software interrupt in case of a problem or to stop a

long fade time.

Update

Data currently on display is resent to the SSM2160. This is

useful when parts are being substituted in the evaluation board,

or when the interface cable is changed.