ETC VS2000

VS2000 PRELIMINARY
VS2000
VS2000 - Headtracking Multichannel
USB Audio Headphone IC / USB DAC
Hardware Features
• Low-power operation
• Single input voltage: Internal voltage regulation for analog, digital, and I/O power
• Operates with a single 12 MHz clock
• Internal PLL clock multiplier
• USB Full Speed hardware
• I/O for user interface
• High-quality on-chip stereo DAC with no
phase error between channels
• Stereo earphone driver capable of driving a
30 Ω load
• Lead-free RoHS-compliant package (Green)
Firmware Features
• 5.1-channel USB Audio Device
• Human Interface Device (HID) Buttons
– Volume Decrement
– Volume Increment
– Pause
– Play
– Rewind
– Fast Forward
• Volume controls also work without HIDaware host
• Four room effect levels selected with Effect
Level Button
• Tracking On / Tracking Off / Bypass modes
selected with Power Button
• Bass and treble controls through USB Audio Feature Unit
• Advanced controls through separate software
• SPI EEPROM boot for special applications
• UART for debugging and special applications
Version 0.3,
2007-09-05
Description
VS2000 is a single-chip multichannel headtracking USB Audio IC with audio output to headphones. VS2000 contains a high-performance lowpower DSP core VS DSP4 , Full Speed USB port,
general purpose I/O pins, SPI, UART, as well as
a high-quality variable-sample-rate stereo DAC,
and an earphone amplifier, and a common voltage
buffer.
When connected to USB, VS2000 firmware controls an ultrasound transmitter and reads ultrasound
receivers to track the movement of the listener’s
head. VS2000 then performs real-time spatial processing to the 5.1 audio channels to position each
sound source correctly depending on the head movement.
An application without headtracking and just with
5.1 audio is also possible.
SPI EEPROM can be used to load code to customize the system.
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VS2000 PRELIMINARY
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Solution
VS2000
CONTENTS
Contents
1
Disclaimer
4
2
Definitions
4
3
Characteristics & Specifications
4
3.1
Absolute Maximum Ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4
3.2
Recommended Operating Conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4
3.3
Analog Characteristics of Audio Outputs . . . . . . . . . . . . . . . . . . . . . . . . . .
5
3.4
Analog Characteristics of Regulators . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5
3.5
Power Consumption . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5
3.6
Digital Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
6
4
5
6
Packages and Pin Descriptions
7
4.1
Packages . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
7
4.2
LQFP-48 Pin Descriptions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
8
VS2000 Functional Blocks
10
5.1
Regulator Section . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
10
5.2
Digital Section . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
11
5.3
Analog Section . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
12
Firmware Operation
13
6.1
SPI Boot . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
14
6.2
UART Boot/Monitor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
14
6.3
Default Firmware Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
15
6.3.1
15
Version 0.3,
2007-09-05
USB Audio Device . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
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6.3.2
7
8
9
VS2000
LIST OF FIGURES
USB Human Interface Device . . . . . . . . . . . . . . . . . . . . . . . . . . .
15
Example Application
17
7.1
19
Usage Hints . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Document Version Changes
20
8.1
Version 0.3, 2007-09-05 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
20
8.2
Version 0.2, 2007-08-31 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
20
8.3
Version 0.1, 2007-06-15 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
20
Contact Information
21
List of Figures
1
Pin Configuration, LQFP-48. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
7
2
VS2000 Block Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
10
3
VS2000 Example Application . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
17
4
VS2000 Unit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
17
5
VS2000 Example Schematic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
18
Version 0.3,
2007-09-05
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1
VS2000
1. DISCLAIMER
Disclaimer
This is a preliminary datasheet. All properties and figures are subject to change.
2
Definitions
B Byte, 8 bits.
b Bit.
Ki “Kibi” = 210 = 1024 (IEC 60027-2).
Mi “Mebi” = 220 = 1048576 (IEC 60027-2).
VS DSP VLSI Solution’s DSP core.
W Word. In VS DSP, instruction words are 32-bit and data words are 16-bit wide.
3
Characteristics & Specifications
3.1 Absolute Maximum Ratings
Parameter
Regulator input voltage
Injected Current on Any Pin
Voltage at Any Digital Input
Operating Temperature
Storage Temperature
1
Symbol
VHIGH
Min
-0.3
-0.3
-40
-65
Max
4.0
±50
IOVDD+0.31
+85
+150
Unit
V
mA
V
◦C
◦C
Must not exceed 3.6 V
3.2
Recommended Operating Conditions
Parameter
Ambient Operating Temperature
Analog and Digital Ground 1
Regulator input voltage3
Input Clock Frequency
Internal Clock Frequency
Master Clock Duty Cycle
Symbol
AGND DGND
VHIGH
XTALI
CLKI
Min
-40
AVDD+0.3
12
40
Typ
0.0
5.0
122
48
50
Max
+85
5.25
48
60
Unit
◦C
V
V
MHz
MHz
%
1
Must be connected together as close the device as possible for latch-up immunity.
To be able to use USB, XTALI must be 12 MHz.
3 4.0 V is required for compliant USB level.
2
Version 0.3,
2007-09-05
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VS2000
VS2000 PRELIMINARY3. CHARACTERISTICS & SPECIFICATIONS
y
Solution
3.3
Analog Characteristics of Audio Outputs
Unless otherwise noted: AVDD=2.8V, CVDD=2.5V, IOVDD=3.3V, TA=-40..+85◦ C, XTALI=12 MHz,
Internal Clock Multiplier 4.0×. DAC tested with full-scale output sinewave, measurement bandwidth 20..20000 Hz,
analog output load: LEFT to CBUF 30Ω, RIGHT to CBUF 30Ω.
Parameter
DAC Resolution
Total Harmonic Distortion
Dynamic Range (DAC unmuted, A-weighted)
S/N Ratio (full scale signal, no load)
Interchannel Isolation (Cross Talk)
Interchannel Isolation (Cross Talk), with GBUF
Interchannel Gain Mismatch
Frequency Response
Full Scale Output Voltage (Peak-to-peak)
Deviation from Linear Phase
Analog Output Load Resistance
Analog Output Load Capacitance
CBUF disconnect current (short-circuit protection)
Symbol
Min
THD
IDR
SNR
Typ
18
Max
0.1
50
-0.5
-0.05
1.3
94
90
75
40
1.5
0.5
0.05
1.7
5
1
AOLR
30
1002
200
Unit
bits
%
dB
dB
dB
dB
dB
dB
Vpp
◦
Ω
pF
mA
1
AOLR may be lower than Typical, but distortion performance may be compromised. Also, there is a maximum
current that the internal regulators can provide.
2
CBUF must have external 10 Ω + 47 nF load, LEFT and RIGHT must have external 20 Ω + 10 nF load for stability.
3.4 Analog Characteristics of Regulators
Parameter
Continuous current, IOVDD
Continuous current, CVDD
Continuous current, AVDD
Dropout voltages, 30 mA
Line regulation, VHIGHmin . . . VHIGHmax
Load regulation, 1 mA . . . 30 mA
Absolute gain setting accuracy 1
Gain step setting accuracy
1
Symbol
Min
Typ
Max
50
50
100
0.3
10
100
+150
+10
-150
-10
Unit
mA
mA
mA
V
mV
mV
mV
%
Absolute level depends on RCAP voltage
3.5
Power Consumption
Parameter
Full operation in example application, Vbus = 5 V
Version 0.3,
2007-09-05
Min
Typ
75
Max
Unit
mA
5
VLSI
VS2000
VS2000 PRELIMINARY3. CHARACTERISTICS & SPECIFICATIONS
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Solution
3.6
Digital Characteristics
Parameter
High-Level Input Voltage
Low-Level Input Voltage
High-Level Output Voltage at IO = -2.0 mA
Low-Level Output Voltage at IO = 2.0 mA
Input Leakage Current
Rise time of all output pins, load = 50 pF
Version 0.3,
2007-09-05
Symbol
Min
0.7×IOVDD
-0.2
0.7×IOVDD
-1.0
Typ
Max
IOVDD+0.31
0.3×IOVDD
0.3×IOVDD
1.0
50
Unit
V
V
V
V
µA
ns
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4
4.1
VS2000
4. PACKAGES AND PIN DESCRIPTIONS
Packages and Pin Descriptions
Packages
LPQFP-48 is lead (Pb) free and also RoHS compliant package. RoHS is a short name of Directive 2002/95/EC on
the restriction of the use of certain hazardous substances in electrical and electronic equipment.
48
1
Figure 1: Pin Configuration, LQFP-48.
LQFP-48 package dimensions are at http://www.vlsi.fi/ .
Version 0.3,
2007-09-05
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4.2
4. PACKAGES AND PIN DESCRIPTIONS
LQFP-48 Pin Descriptions
Pin Name
XRESET
GPIO0 0
GPIO0 1
GPIO0 2
GPIO0 3
DGND0
IOVDD1
TEST
GPIO0 4
GPIO0 5
GPIO0 6
GPIO0 7
GPIO0 8
GPIO0 9
GPIO0 10
GPIO0 12
GPIO0 13
DGND1
IOVDD2
GPIO0 11
GPIO0 14
XCS / GPIO1 0
SCLK / GPIO1 1
SI / GPIO1 2
SO / GPIO1 3
TX / GPIO1 4
RX / GPIO1 5
XTALI
XTALO
IOVDD
DGND2
CVDD
VHIGH
AVDD
USBP
USBN
PWRBTN
AGND0
AVDD1
RIGHT
AGND1
AGND2
CBUF
AVDD2
RCAP
AVDD3
LEFT
AGND3
Version 0.3,
VS2000
2007-09-05
LQFP
Pin
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
Pin
Type
DI
DIO
DIO
DIO
DIO
DGND
IOPWR
DI
DIO
DIO
DIO
DIO
DIO
DIO
DIO
DIO
DIO
DGND
IOPWR
DIO
DIO
DIO
DIO
DIO
DIO
DIO
DIO
AI
AO
IOPWR
DGND
CPWR
PWR
APWR
AIO
AIO
AIO
APWR
APWR
AO
APWR
APWR
AO
APWR
AIO
APWR
AO
APWR
Function
Active low asynchronous reset, schmitt-trigger input
General-purpose IO Port 0, bit 0
General-purpose IO Port 0, bit 1
General-purpose IO Port 0, bit 2
General-purpose IO Port 0, bit 3
Core & I/O ground
I/O power supply
Test mode input (active high), connect to DGND
General-purpose IO Port 0, bit 4
General-purpose IO Port 0, bit 5
General-purpose IO Port 0, bit 6
General-purpose IO Port 0, bit 7
General-purpose IO Port 0, bit 8
General-purpose IO Port 0, bit 9
General-purpose IO Port 0, bit 10
General-purpose IO Port 0, bit 12
General-purpose IO Port 0, bit 13
Core & I/O ground
I/O power supply
General-purpose IO Port 0, bit 11
General-purpose IO Port 0, bit 14
SPI XCS / General-Purpose I/O Port 1, bit 0
SPI CLK / General-Purpose I/O Port 1, bit 1
SPI MISO / General-Purpose I/O Port 1, bit 2
SPI MOSI / General-Purpose I/O Port 1, bit 3
UART TX / General-Purpose I/O Port 1, bit 4
UART RX / General-Purpose I/O Port 1, bit 5
Crystal input
Crystal output
I/O power supply, Regulator output
Core & I/O ground
Core power supply, Regulator output
Power supply, Regulator input
Analog power supply, Regulator output
USB differential + in / out, controllable 1.5kΩ pull-up
USB differential - in / out
Power button for Regulator startup (and Power Key)
Analog ground
Analog power supply
Right channel output
Analog ground
Analog ground
Common voltage buffer for headphones
Analog power supply
Filtering capacitance for reference
Analog power supply
Left channel output
Analog ground
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VS2000 PRELIMINARY
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Solution
VS2000
4. PACKAGES AND PIN DESCRIPTIONS
Pin types:
Type
DI
DO
DIO
AI
AO
Version 0.3,
Description
Digital input, CMOS Input Pad
Digital output, CMOS Input Pad
Digital input/output
Analog input
Analog output
2007-09-05
Type
AIO
APWR
DGND
CPWR
IOPWR
Description
Analog input/output
Analog power supply pin
Core or I/O ground pin
Core power supply pin
I/O power supply pin
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5
VS2000
5. VS2000 FUNCTIONAL BLOCKS
VS2000 Functional Blocks
LEFT
RIGHT
CBUF
RCAP
VHIGH
PWRBTN
Reference
AVDD1
AVDD2
AVDD3
Stereo
Earphone
Driver
Stereo
DAC
Common
Voltage
Driver
Regulator
Regulator
Voltage
Monitor
Regulator
USBP
USPN
XCS/GPIO1[0]
SCLK/GPIO1[1]
SI/GPIO1[2]
SO/GPIO1[3]
USB
Serial
Data/
Control
Interface
CVDD
X RAM
X ROM
VSDSP4
processor
UART
Y RAM
XTALO
XTALI
Clock
Y ROM
NAND
Flash
Interface/
General IO
I RAM
Control/
GPIO0[8...14]
AVDD
<1.6V
reset
RX/GPIO1[5]
TX/GPIO1[4]
Data/
GPIO0[0...7]
IOVDD
I ROM
TEST
XRESET
IOVDD1
IOVDD2
Figure 2: VS2000 Block Diagram
5.1 Regulator Section
The VHIGH pin in the regulator section is used as a common main power supply for voltage regulation. This
input is connected to three internal regulators, which are activated when the PWRBTN pin is set high for about one
millisecond, so that AVDD starts to rise and reaches about 1.5 V. After the PWRBTN has given this initial start
current, the regulators reach their default voltages even if the PWRBTN is released. VHIGH must be sufficiently
(about 0.3 V) above the highest regulated power (normally AVDD) so that regulation can be properly performed.
The PWRBTN state can also be read by software, so it can be used as one of the user interface buttons.
A power-on reset monitors the core voltage and asserts reset if CVDD drops below 1.6 V. It is also possible to
force a reset by keeping PWRBTN pressed for longer than approximately 5.6 seconds. A watchdog counter and
the XRESET pin can also generate a reset for the device.
Resets do not cause the regulators to shut down, but they restore the default regulator voltages. After boot the
firmware and user software can change the voltages.
Return to power-off is possible only with active software control (VSDSP writes the regulator shutdown bit), or
when VHIGH voltage is removed for a sufficiently long time. In the default firmware player the power button has
to be pressed for 2 seconds to make the software powerdown the system and turn the regulators off.
Version 0.3,
2007-09-05
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VS2000 PRELIMINARY
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5.2
VS2000
5. VS2000 FUNCTIONAL BLOCKS
Digital Section
Two of the regulators provide power supply for the digital section.
IOVDD is used for the level-shifters of the digital I/O and crystal oscillator. The IOVDD regulator output must be
connected to IOVDD1 and IOVDD2 input pins, because they are not connected internally. Proper bypass capacitors
should also be used. After reset the I/O voltage is 1.8 V, and firmware raises it to 3.3 V.
All other digital is powered from core voltage (CVDD). The core voltage is internally connected, and the CVDD
pin should have a proper bypass capacitors.
Clock
The crystal amplifier uses a crystal connected to XTALI and XTALO. An external logic-level input clock can also
be used. When VS2000 is used with USB, 12 MHz input clock must be used.
An internal phase-locked loop (PLL) generates the internal clock by multiplying the input clock by 1.0×, 1.5×,
. . . , 4.0×. In normal operating mode the clock is 4.0×12 MHz = 48 MHz. During USB suspend the PLL is off.
XRESET disables clock buffer and puts the digital section into powerdown mode.
VSDSP4
VSDSP4 is VLSI Solution’s proprietary digital signal processor with a 32-bit instruction word, two 16-bit data
buses, and both 16-bit and 32/40-bit arithmetic.
IROM, XROM, and YROM contain the firmware, including the default application. Most of the instruction RAM
and some of the X and Y data RAM’s can be used to customize and extend the functionality.
UART
An asynchronous serial port is used for debugging and special applications. The default speed is 115200 bps. RX
and TX pins can also be used for general-purpose I/O when the UART is not required.
SPI
A synchronous serial port peripheral is used for SPI EEPROM boot, and can be used to access other SPI peripherals
(for example LCD or SED) by using another chip select. The SPI is only used for boot if the XCS pin has a high
level after reset (pull-up resistor attached). These pins can also be used for general-purpose I/O when the SPI is
not required.
The firmware uses SPI pins SO and SCLK for ultrasound transmitter.
Version 0.3,
2007-09-05
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VS2000 PRELIMINARY
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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, because 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
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Solution
6
VS2000
6. FIRMWARE OPERATION
Firmware Operation
The firmware uses the following pins (see the example schematics in Section 7):
Pin
VHIGH
PWRBTN
USBN
USBP
GPIO0 0
GPIO0 1
GPIO0 2
GPIO0 3
GPIO0 4
GPIO0 5
GPIO0 6
GPIO0 7
GPIO0 8
GPIO0 9
GPIO0 10
GPIO0 11
GPIO0 12
GPIO0 13
GPIO0 14
GPIO1 0 / XCS
GPIO1 1 / SCLK
GPIO1 2 / SI
GPIO1 3 / SO
GPIO1 4 / TX
GPIO1 5 / RX
Description
VBUS with diode to VHIGH
Power button starts regulator + VBUS-triggered (Mode Select)
external 1 MΩ pull-up
external 1 MΩ pull-up
external 1 MΩ pull-down resistor, Key 1 connects a 100 kΩ pull-up resistor (Vol-)
external 1 MΩ pull-down resistor, Key 2 connects a 100 kΩ pull-up resistor (Vol+)
external 1 MΩ pull-down resistor, Key 3 connects a 100 kΩ pull-up resistor (Pause)
external 1 MΩ pull-down resistor, Key 4 connects a 100 kΩ pull-up resistor (Play)
external 1 MΩ pull-down resistor, Key 5 connects a 100 kΩ pull-up resistor (Rewind)
external 1 MΩ pull-down resistor, Key 6 connects a 100 kΩ pull-up resistor (Fast Forward)
external 1 MΩ pull-down resistor, Key 7 connects a 100 kΩ pull-up resistor (Effect Level Select)
external 100 kΩ pull-up resistor
USB LED - Red
Effect Level LED - Green (PWM-controlled)
Tracking LED - Red
Tracking LED - Green
Headtracker input right
Headtracker input left
Audio LED, External power control, with 1 MΩ pull-down resistor
external pull-up to enable SPI EEPROM boot
820 Hz headtracker transmit / SPI EEPROM SCLK
SPI EEPROM MISO
40 kHz headtracker transmit / SPI EEPROM MOSI
UART transmit
UART receive
Tracking LEDs indicate the operation mode:
Green On
Green Off, Red Off
Green Off, Red On
Tracking On, RED On if tracking error is detected
Tracking Off, spatial processing active
Bypass mode, no spatial processing, down-mixing only
USB LED is lit when setup packets are received, i.e. during device configuration, and when audio controls are
changed.
Audio LED is lit when audio data is transferred and is turned off after a short timeout when audio transmission
stops.
Version 0.3,
2007-09-05
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VLSI
VS2000 PRELIMINARY
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Solution
6.1
VS2000
6. FIRMWARE OPERATION
SPI Boot
The first boot method is SPI EEPROM. If GPIO1[0] is low after reset, SPI boot is skipped. If GPIO1[0] is high, it
is assumed to have a pull-up resistor and SPI boot is tried.
First the first four bytes of the SPI EEPROM are read using 16-bit address. If the bytes are “VLSI”, a 16-bit
EEPROM is assumed and the boot continues. If the last 3 bytes are read as “VLS”, a 24-bit EEPROM is assumed
and boot continues in 24-bit mode. Both 16-bit and 24-bit EEPROM should have the “VLSI” string starting at
address 0, and the rest of the boot data starting at address 4. If the identification is not found, SPI EEPROM boot
is skipped.
Boot records are read from EEPROM until an execute record is reached. Unknown records are skipped using the
data length field.
Byte
0
1,2
3, 4
5..
6.2
Description
type 0=I-mem 1=X-mem 2=Y-mem 3=execute
data len lo, hi – data length in bytes
address lo, hi – record address
data*
UART Boot/Monitor
When byte 0xef is sent to RX at 115200 bps, the firmware enters monitor mode and communicates with vs3emu.
Memory contents can be displayed, executables can be loaded and run, or the firmware code can be restarted or
continued.
The UART is also a convenient way to program or reprogram the SPI EEPROM.
Version 0.3,
2007-09-05
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VS2000 PRELIMINARY
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Solution
6.3
VS2000
6. FIRMWARE OPERATION
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.
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6. FIRMWARE OPERATION
In both tracking modes the full 3D processing is active. In the bypass-mode the 3D processing is replaced by a
simple 6-channel to 2-channel matrixing operation.
The power button is not a Human Interface Device button.
Effect Level Button
The effect level button selects between four predefined levels of room response. The default levels are off, low,
medium, and high. The default setting is the medium level.
The effect level button is not a Human Interface Device button.
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7. EXAMPLE APPLICATION
Example Application
Figure 3: VS2000 Example Application
The example application consists of five parts.
1. VS2000 Unit - contains the VS2000 chip and other active electronics, buttons and LEDs.
2. Transmitter - ultrasound transmitter element, is powered and controlled by VS2000 Unit.
3. Sensors - ultrasound receivers, are read by VS2000 Unit.
4. USB - the audio source. USB also powers the system.
5. Headphones - for audio output.
Figure 4: VS2000 Unit
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7. EXAMPLE APPLICATION
Figure 5: VS2000 Example Schematic
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7. EXAMPLE APPLICATION
Usage Hints
Linux
Mplayer requires the following options to play the 6-channel audio instead of 2-channel: -channels 6 -af
channels=6:6:0:0:1:1:2:4:3:5:4:2:5:3. The first option selects six channels, and the second option
corrects the channel mapping. Mplayer does not determine the output channel mapping automatically.
Also an option like -ao alsa:device=hw=1.0 may be needed to select the USB Audio Device in case the
system has multiple audio devices.
MAC
The MAC system player seems to only play the two-channel mix of a DVD, and can not be configured for multichannel sound, as far as we could determine.
Mplayer requires the following options to play the 6-channel audio instead of 2-channel: -channels 6 -af
channels=6:6:0:0:1:1:2:4:3:5:4:2:5:3. The first option selects six channels, and the second option
corrects the channel mapping. Mplayer does not determine the output channel mapping automatically.
Windows 2000Pro, XP, Vista
Windows MediaPlayer should play all the channels and it also processes the channel order information, thus plays
the channels in the right order. Some old third-party DVD player applications only play 2-channel audio.
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8. DOCUMENT VERSION CHANGES
Document Version Changes
This chapter describes the most important changes to this document.
8.1
Version 0.3, 2007-09-05
• Example application picture and board photo added.
• First public release.
8.2
Version 0.2, 2007-08-31
• Headtracker left and right swapped.
• Example schematic and pictures updated.
• Usage hints chapter added.
8.3
Version 0.1, 2007-06-15
• First pre-release version.
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9. CONTACT INFORMATION
9 Contact Information
VLSI Solution Oy
Entrance G, 2nd floor
Hermiankatu 8
FIN-33720 Tampere
FINLAND
Fax: +358-3-3140-8288
Phone: +358-3-3140-8200
Email: [email protected]
URL: http://www.vlsi.fi/
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