
VLSI
Solution
y
VS2000 PRELIMINARY
VS2000
6. FIRMWARE OPERATION
6
Firmware Operation
The firmware uses the following pins (see the example schematics in Section 7):
Pin
Description
VHIGH
VBUS with diode to VHIGH
PWRBTN
Power button starts regulator + VBUS-triggered (Mode Select)
USBN
external 1 MΩ pull-up
USBP
external 1 MΩ pull-up
GPIO0 0
external 1 MΩ pull-down resistor, Key 1 connects a 100 kΩ pull-up resistor (Vol-)
GPIO0 1
external 1 MΩ pull-down resistor, Key 2 connects a 100 kΩ pull-up resistor (Vol+)
GPIO0 2
external 1 MΩ pull-down resistor, Key 3 connects a 100 kΩ pull-up resistor (Pause)
GPIO0 3
external 1 MΩ pull-down resistor, Key 4 connects a 100 kΩ pull-up resistor (Play)
GPIO0 4
external 1 MΩ pull-down resistor, Key 5 connects a 100 kΩ pull-up resistor (Rewind)
GPIO0 5
external 1 MΩ pull-down resistor, Key 6 connects a 100 kΩ pull-up resistor (Fast Forward)
GPIO0 6
external 1 MΩ pull-down resistor, Key 7 connects a 100 kΩ pull-up resistor (Effect Level Select)
GPIO0 7
external 100 kΩ pull-up resistor
GPIO0 8
USB LED - Red
GPIO0 9
Effect Level LED - Green (PWM-controlled)
GPIO0 10
Tracking LED - Red
GPIO0 11
Tracking LED - Green
GPIO0 12
Headtracker input right
GPIO0 13
Headtracker input left
GPIO0 14
Audio LED, External power control, with 1 MΩ pull-down resistor
GPIO1 0 / XCS
external pull-up to enable SPI EEPROM boot
GPIO1 1 / SCLK
820 Hz headtracker transmit / SPI EEPROM SCLK
GPIO1 2 / SI
SPI EEPROM MISO
GPIO1 3 / SO
40 kHz headtracker transmit / SPI EEPROM MOSI
GPIO1 4 / TX
UART transmit
GPIO1 5 / RX
UART receive
Tracking LEDs indicate the operation mode:
Green On
Tracking On, RED On if tracking error is detected
Green Off, Red Off
Tracking Off, spatial processing active
Green Off, Red On
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
13