CY7C65621/31
Document #: 001-52934 Rev. **
Page 11 of 24
Hub Descriptor
Byte
All Speed
Field Name
Description
0
0x09
bLength
9 Bytes
1
0x29
bDescriptorType
Hub Descriptor
20x04[6]
0x02
bNbrPorts
Number of ports supported, CY7C65631.
Number of ports supported, CY7C65621.
3,4
0x0089[6]
wHubCharacteristics
b1, b0: Logical Power Switching Mode
00: Ganged power switching (all ports’ power at once)
01: Individual port power switching (Default in CY7C65621/31)
b2: Identifies a Compound Device,
0: Hub is not part of a compound device (Default in CY7C65621/31),
1: Hub is part of a compound device.
b4, b3: Overcurrent Protection Mode
00: Global Overcurrent Protection. The hub reports overcurrent as a
summation of all ports’ current draw, without a breakdown of individual port
overcurrent status.
01: Individual Port Overcurrent Protection. The hub reports overcurrent on a
per-port basis. Each port has an over-current status (Default in
CY7C65621/31).
1X: No Overcurrent Protection. This option is allowed only for bus powered
hubs that do not implement overcurrent protection.
b6, b5: TT Think Time
00: TT requires at most eight FS bit times of inter transaction gap on a full or
low speed downstream bus (Default in CY7C65621/31).
b7: Port Indicators Supported,
0: Port Indicators are not supported on its downstream facing ports and the
SetPortIndicator request has no effect.
1: Port Indicators are supported on its downstream facing ports and the
SetPortIndicator request controls the indicators. See Functional Overview and
Supported USB Requests. (Default in CY7C65621/31).
b15,. b8: Reserved
50x32[6]
bPwrOn2PwrGood
Time from when the port is powered to when the power is good on that port
60x28[6]
0xAE[6]
bHubContrCurrent
Maximum current requirement for the Hub Controller at full speed.
Maximum current requirement for the Hub Controller at high speed.
70x00[6]
bDeviceRemovable
Indicates if the logical port has a removable device attached (0 = removable,
1 = non removable)
80xFF[6]
bPortPwrCtrlMask
Required for compatibility with software written for 1.0 compliant devices
Note
6. This value is configured through the external EEPROM.
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