Philips Universal Serial Bus ISP1122, Specification Sheet, Page: 16 / 48

Philips Semiconductors
ISP1122
USB stand-alone hub
Product specification Rev. 03 — 29 March 2000 16 of 48
9397 750 07002 © Philips Electronics N.V. 2000. All rights reserved.
[1] Selected by input SP/BP.
[2] Value in units of 2 mA.
Table 11: Configuration descriptor
Values in square brackets are optional.
Offset
(bytes) Field name Size
(bytes) Value
(Hex) Comments
0 bLength 1 09 descriptor length = 9 bytes
1 bDescriptorType 1 02 type = CONFIGURATION
2 wTotalLength 2 19, 00 total length of configuration, interface
and endpoint descriptors (25 bytes)
4 bNumInterfaces 1 01 one interface
5 bConfigurationValue 1 01 configuration value = 1
6 iConfiguration 1 00 no configuration string
7 bmAttributes 1 E0 self-powered with remote wake-up
[1]
A0 bus-powered with remote wake-up
[1]
8 MaxPower
[2]
1 32 100 mA (default)
[00] 0 mA (using an external EEPROM)
[FA] 500 mA (using an external EEPROM)
Table 12: Interface descriptor
Offset
(bytes) Field name Size
(bytes) Value
(Hex) Comments
0 bLength 1 09 descriptor length = 9 bytes
1 bDescriptorType 1 04 type = INTERFACE
2 bInterfaceNumber 1 00 -
3 bAlternateSetting 1 01 no alternate setting
4 bNumEndpoints 1 01 status change (interrupt) endpoint
5 bInterfaceClass 1 09 HUB_CLASSCODE
6 bInterfaceSubClass 1 00 -
7 bInterfaceProtocol 1 00 no class-specific protocol
8 bInterface 1 00 no interface string
Table 13: Endpoint descriptor
Offset
(bytes) Field name Size
(bytes) Value
(Hex) Comments
0 bLength 1 07 descriptor length = 7 bytes
1 bDescriptorType 1 05 type = ENDPOINT
2 bEndpointAddress 1 81 endpoint 1, direction: IN
3 bmAttributes 1 03 interrupt endpoint
4 wMaxPacketSize 2 01, 00 packet size = 1 byte
6 bInterval 1 FF polling interval (255 ms)