Tait TM8000 Series, Applications Manual, Page: 61 / 136

TM8000 3DK Hardware Developer’s Kit Application Manual Programmable I/O Lines 61
September 2003 © Tait Electronics Ltd
3.1.18 Force Audio PA Off
Application
This input signal is used to deactivate the audio PA. This action is required,
for example, to allow the use of a telephone handset for which—when it is
taken off hook—the audio PA should be deactivated to prevent the audio
from coming out of the internal or remote speaker. Please refer also to
Figure 3.8 on page 60 .
Configuration
Configure an input line and associate it with this action. Set the active state
(high or low) and the debounce time (0 to 100ms).
Timing
When this input line is activated and the audio PA is on, there will be no
significant delay before the speaker audio is muted. After 100ms the audio
PA will be fully powered down and current consumption will reduce by
50 mA.
Description
When this input line is activated, the radio mutes the audio PA. If the audio
PA is already muted, no action occurs.
When this input line is deactivated, the audio PA reverts to its previous state.
If the input line is active while the radio is powered up, it must be re-applied
for the action to be carried out.
Activation of ‘ Force Audio PA Off ’ input line takes precedence over the
‘ Force Audio PA On ’ input line. When both inputs are active at the same
time, the speaker is disabled but any audio signal present is still output
through RX_AUD.
Related Actions
A related ‘ Force Audio PA On ’ input signal exists, for which another input
line can be assigned. Separate input lines are needed because deactivation of
each line should release the corresponding action rather than forcing the
audio PA into the opposite state.
The ‘ Mute Audio Output Path ’ input signal activates the Rx audio path
only. The ‘ Unmute Audio Output Path ’ input signal deactivates the Rx
audio path only.