VS1000 Datasheet, PDF (17/23 Pages) List of Unclassifed Manufacturers – Ogg Vorbis Player IC with USB and NAND FLASH Interface

VLSI
Solution ^y
VS1000b
VS1000
7. FIRMWARE OPERATION
7.4 Default Firmware Features
7.4.1 USB Mass Storage and Audio Device
When USB cable insertion is detected by the firmware, playing of the current file is stopped and 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 USB peripheral is initialized, and the USB pull-up resistor is enabled.
If GPIO0 6 has a pull-up resistor, VS1000 appears as an USB Audio Device. If GPIO0 6 has a pull-down resistor,
VS1000 appears as an USB Mass Storage Device.
If during power-on the NAND FLASH contained a valid boot sector, the NAND FLASH disk will be used with
the mass storage device. The NAND FLASH disk requires a filesystem-level formatting before it can be used. If
NFCE had a pull-down instead of pull-up, or if a valid boot sector was not found, a RAM disk is used instead.
The RAM disk is preformatted and can be used immediately, but it does not retain its contents between USB
detachment and insertion. The RAM disk is only intended for loading software through USB. You can copy a
file VS1000 B.RUN to RAM disk and it will be automatically run when you disconnect the USB cable. This
mechanism can be used to program the NAND FLASH boot sector (perhaps containing custom boot code), and
also for programming a SPI EEPROM in case NAND FLASH is not used in the application.
7.4.2 Default Player Application
When the USB cable is detached, the contents of the disk is checked. If the disk seems to contain a FAT16 or
FAT32 filesystem, a cleanup of unused sectors is performed. The cleanup makes the disk perform faster the next
time something is written on it. If a full disk has been formatted or emptied, this cleanup can take considerable
time, even 30 seconds or more. After the cleanup is finished the player starts to play files.
Note: normally Windows formats smaller than about 16 MB disks as FAT12. The player has only partial support for
FAT12 disks: no cleanup is performed, subdirectories are not allowed, and files are assumed not to be fragmented.
If disks as small as or smaller than this are required, it is possible to format them as FAT16 with the following
command. format e: /A:512 /FS:FAT
The default player application only decodes Ogg Vorbis files, but it can be extended to allow some simple codecs,
like a WAV decoder.
In addition to the power button, 5 keys are connected to GPIO0 [4:0] 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. The resistors are needed
because these lines are also used for NAND FLASH communication. The keys are read approximately 16 times
per second.
The key control can be changed by replacing the default key mapping table. The default user interface uses six
buttons.
Button
POWER
KEY1
KEY2
KEY3
KEY4
KEY5
Short Press < 1 second
Power On, Pause / Play
Volume Down
Volume Up
Previous
Next
EarSpeaker
Long Press >= 1 second
Power off (pressed for 2 seconds)
Volume Down
Volume Up
Rewind
Fast Forward
Random On / Off
Version 1.0, 2007-09-11
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