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AS: Set Subwoofer Volume

FAST Serial Protocol: Overview & First Steps

This documentation section is about the FAST Serial Protocol (FSP) commands, which are the low-level commands a host computer sends to a FAST board. Most FAST Pinball makers do not need to know about these details, since the pinball game framework (such as the Mission Pinball Framework) handles this communication for you.

If you're writing your own game framework, read the overview of how FSP works and how to connect first.

The AS: command is used to set the subwoofer volume of the FAST Audio Interface Board. The volume level is a value between 0x00 and 0x3f (decimal 0-63). The mode of the audio system can affect the subwoofer behavior. See the AM: command for details. Depending on the mode set, the subwoofer can be disabled or do automatic crossfade when the headphones are plugged in.

Command Syntax

AS:<DATA><CR>

Data is a a volume value from 00 to 3F (0-63)

The return value is the same as what was passed in.

The command AS:18<CR> will return AS:18<CR>, confirming the subwoofer volume was set to 18 hex, which is 24 decimal, or about 38% volume (24/63).

If the mode of the subwoofer is set to AUDIO_HEADPHONE_MODE_DUCK (see AM: command) the set subwoofer volume will increase or decrease over time based on the new settings.

Documentation Feedback? Requests? Confused?

Hi! I'm Brian, and I'm responsible for the documentation at FAST Pinball. If you have any feedback, requests, corrections, ideas, or any other thoughts about this documentation, please let me know! You can email me at brian@fastpinball.com. Thanks!

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