2009 - 2015 Microchip Technology Inc. DS00002005A-page 29
USB2250/50i/51/51i
7.2.5.6 CEh-D2h: Inquiry Product String
7.2.5.7 D3h: Dynamic Number of LUNs
7.2.5.8 D4h-D7h: Device to LUN Mapping
7.2.5.9 D8h-FBh: Not Applicable
7.2.5.10 FCh-FFh: Non-Volatile Storage Signature
Byte Name Description
4:0 INQ_PRD_STR If bit 4 of the 1st attribute byte is set, the device will use these strings in
response to a USB inquiry command, instead of the USB descriptor
manufacturer and product ID strings.
Byte Name Description
7:0 DYN_NUM_LUN These bytes are used to specify the number of LUNs the device exposes to
the host. These bytes are also used for icon sharing by assigning more than
one LUN to a single icon. This is used in applications where the device utilizes
a combo socket and the OEM wishes to have only a single icon displayed for
one or more interfaces.
If this field is set to "FF", the program assumes that you are using the default
value and icons will be configured per the default configuration.
Byte Name Description
3:0 DEV_LUN_MAP These registers map a device controller (SD/MMC, SM, and MS) to a Logical
Unit Number (LUN). The device reports the mapped LUNs to the USB host in
the USB descriptor during enumeration. The icon installer associates custom
icons with the LUNs specified in these fields.
Setting a register to "FF" indicates that the device is not mapped. Setting all
of the DEV_LUN_MAP registers for all devices to "FF" forces the use of the
default mapping configuration. Not all configurations are valid. Valid
configurations depend on the hardware, packaging, and OEM board layout.
The number of unique LUNs mapped must match the value in the Section
7.2.5.7, "D3h: Dynamic Number of LUNs," on page 29.
Byte Name Description
35:0 Not Applicable Not Applicable.
Byte Name Description
3:0 NVSTORE_SIG This signature is used to verify the validity of the data in the first 256 bytes of
the configuration area. The signature must be set to ‘ATA2’ for
USB2250/50i/51/51i.
