VS1000 Datasheet, PDF (14/23 Pages) List of Unclassifed Manufacturers – Ogg Vorbis Player IC with USB and NAND FLASH Interface

VLSI
Solution ^y
VS1000b
VS1000
6. VS1000 FUNCTIONAL BLOCKS
NAND FLASH Interface
The NAND FLASH peripheral calculates a simple error-correcting code (ECC), and automates some of the com-
munication with a NAND FLASH chip. The firmware uses the peripheral to access both small-page (512+16 B
pages) and large-page (2048+64 B pages) NAND FLASH chips. The first sector in the FLASH tells the firmware
how it should be accessed.
The NAND FLASH interface pins can also be used as general-purpose I/O. The default firmware uses GPIO0 [4:0]
for keys, and GPIO0 [7:6] for other purposes. Pull-up and pull-down resistors must be used for these connections
so that the data transfer to and from the NAND FLASH isn’t disturbed when keys are pressed.
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 both USB Mass Storage Device and USB Audio Device.
Which device is activated depends on the state of GPIO0 6 when the USB connection is detected. 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.
6.3 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 1.0, 2007-09-11
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