VS2000 Datasheet, PDF (12/21 Pages) List of Unclassifed Manufacturers – Headtracking Multichannel USB Audio Headphone IC / USB DAC

VLSI
Solution ^y
VS2000 PRELIMINARY
VS2000
5. VS2000 FUNCTIONAL BLOCKS
USB
The USB peripheral handles USB 1.1 Full Speed harware protocol. Low speed communication is not supported,
but is correctly ignored. The USBP pin has a software-controllable 1.5kΩ pull-up.
A control endpoint (1 IN and 1 OUT) and upto 6 other endpoints (3 IN and 3 OUT) can be used simultaneously.
Bulk, interrupt, and isochronous transfer modes are selectable for each endpoint. USB receive from USB host to
device (OUT) uses a 2 KiB buffer, thus allowing very high transfer speeds. USB transmit from device to USB host
(IN) also uses a 2 KiB buffer and allows all IN endpoints to be ready to transmit simultaneously. Double-buffering
is also possible, but not usually required.
The firmware uses the USB peripheral to implement a 6-channel USB Audio Device and USB Human Interface
Device.
5.3 Analog Section
The third regulator provides power for the analog section.
The analog section consists of digital to analog converters and earphone driver. This includes a buffered common
voltage generator (CBUF, around 1.2 V) that can be used as a virtual ground for headphones.
The AVDD regulator output pin must be connected to AVDD1..AVDD3 pins with proper bypass capacitors, be-
cause they are not connected internally.
The USB pins use the internal AVDD voltage, and the firmware configures AVDD to 3.6 V when USB is attached.
Low AVDD voltage can be monitored by software. Currently the firmware does not take advantage of this feature.
CBUF contains a short-circuit protection. It disconnects the CBUF driver if pin is shorted to ground. In practise
this only happens with external power regulation, because there is a limit to how much power the internal regulators
can provide.
Version 0.3, 2007-09-05
12