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SLES081A − JUNE 2003 – REVISED MAY 2004
USB INTERFACE
Control data and audio data are transferred to the PCM2704/5/6/7 via D+ (pin 9 for PCM2704/5, pin 23 for
PCM2706/7) and D– (pin 8 for PCM2704/5, pin 22 for PCM2706/7). D+ should be pulled up with a 1.5-kΩ (±±5%
resistor. To avoid back voltage in self-powered operation, the device must not provide power to the pullup resistor
on D+ while V
of the USB port is inactive.
BUS
All data to/from the PCM2704/5/6/7 are transferred at full speed. The following information is provided in the device
descriptor. Some parts of the device descriptor can be modified through external ROM (PCM2704/6), SPI
(PCM2705/7), or internal mask ROM on request.
Table 3. Device Descriptor
USB revision
1.1 compliant
Device class
0x00 (device defined interface level)
0x00 (not specified)
Device subclass
Device protocol
Max packet size for endpoint 0
Vendor ID
0x00 (not specified)
8 bytes
0x08BB (default value, can be modified)
Product ID
0x2704/0x2705/0x2706/0x2707 (These values correspond to the model number, and the value can be
modified.)
Device release number
Number of configurations
Vendor strings
1.0 (0x0100)
1
“Burr-Brown from TI” (default value, can be modified)
“USB Audio DAC” (default value, can be modified)
Not supported
Product strings
Serial number
The following information is contained in the configuration descriptor. Some parts of the configuration descriptor can
be modified through external ROM (PCM2704/6), SPI (PCM2705/7), or on request.
Table 4. Configuration Descriptor
Interface
Three interfaces
Power attribute
Max power
0x80 or 0xC0 (bus-powered or self-powered, depending on PSEL; no remote wake up. This value can be modified.)
0x0A, 0x32 or 0xFA (20 mA for self-powered, 100 mA or 500 mA for bus-powered, depending on PSEL and HOST. This
value can be modified.)
The following information is contained in the string descriptor. Some parts of the string descriptor can be modified
through external ROM (PCM2704/6), SPI (PCM2705/7), or on request.
Table 5. String Descriptor
#0
#1
#2
0x0409
Burr-Brown from TI (default value, can be modified)
USB Audio DAC (default value, can be modified)
16
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