VS2000 Datasheet, PDF (15/21 Pages) List of Unclassifed Manufacturers – Headtracking Multichannel USB Audio Headphone IC / USB DAC

VLSI
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VS2000 PRELIMINARY
VS2000
6. FIRMWARE OPERATION
6.3 Default Firmware Features
When USB cable insertion is detected by the firmware, USB handling code is started. The internal clock is
configured to 4.0× 12 MHz = 48 MHz, the analog power is configured to 3.6 V, the core power to 2.5 V, the USB
peripheral is initialized, and the USB pull-up resistor is enabled.
In addition to the power button, upto 7 keys are connected to GPIO0[6..0] so that they connect a 100 kΩ pull-up to
the I/O when the button is pressed, and 1 MΩ pull-downs keep the lines low otherwise.
Some of the keys are used for different direct modes, the rest are available to PC through USB Human Interface
Device.
6.3.1 USB Audio Device
VS2000 appears as an USB Composite Device with USB Audio Device and USB Human Interface Device. The
USB Audio Device has 6 16-bit channels, and a feature unit that includes master volume, master mute, master
bass, and master treble controls. These controls can be changed using system tools (in Windows using the volume
control panel and advanced audio settings).
Headtracker transmit is only enabled when audio transmission is active.
6.3.2 USB Human Interface Device
The USB Human Interface Device (HID) transmits information about the state of the device buttons to the host
machine. With proper software HID can also be used for reading and writing VS2000 memory, for example
monitoring the headtracker state, and changing some advanced features.
Volume Decrement, Volume Increment
Volume can be turned up or down with 0.5 dB steps using the volume buttons. A short press changes the volume
by 0.5 dB, a long press will change the volume by approximately 8 dB every second. Using the volume buttons is
always possible, regardless of whether the host machine supports USB Human Interface Devices or not.
If the host machine supports USB Human Interface Devices, it can detect the press of volume buttons and set the
volume using the USB Audio Device controls.
Pause, Play, Rewind, Fast Forward
These buttons are Human Interface Device buttons only. Their operation depends on the host machine, and the
application that is active at the time.
Power Button
A press of the power button turns on the system. Insertion of the device to the USB port can also turn the unit on.
A long press (2 seconds) of the power button will turn off the device.
Short press of the power button switches the processing mode between Tracking On, Tracking Off, and Bypass.
Version 0.3, 2007-09-05
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