Cypress EZ-USB HX2LP manual Configuration Options, Hub Descriptor, Default 0xD0 Load, Byte Value

PRELIMINARYCY7C656xx

8.8Hub Descriptor

Byte	All Speed	Field Name	Description
0	0x09	bLength	9 Bytes
1	0x29	bDescriptorType	HUB Descriptor
2	0x04[11]	bNbrPorts	Number of ports supported, CY7C65640B or CY7C65630.
	0x02		Number of ports supported, CY7C65620.
3,4	0x0089[11]	wHubCharacteristics	b1, b0: Logical Power Switching Mode
			00: Ganged power switching (all ports’ power at once)
			01: Individual port power switching (Default in CY7C656xx)
			b2: Identifies a Compound Device,
			0: Hub is not part of a compound device (Default in CY7C656xx),
			1: Hub is part of a compound device.
			b4, b3: Over-current 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 CY7C656xx).
			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 8 FS bit times of inter transaction gap on a
			full-/low-speed downstream bus (Default in CY7C656xx).
			b7: Port Indicators Supported,
			0: Port Indicators are not supported on its downstream facing ports and
			the PORT_INDICATOR request has no effect.
			1: Port Indicators are supported on its downstream facing ports and the
			PORT_INDICATOR request controls the indicators. See Section 5.0 and 10.0
			(Default in CY7C656xx).
			b15,. b8: Reserved
5	0x32[11]	bPwrOn2PwrGood	Time from when the port is powered to when the power is good on that port
6	0x28[11]	bHubContrCurrent	Maximum current requirement for the Hub Controller at full-speed.
	0xAE[11]		Maximum current requirement for the Hub Controller at high-speed.
7	0x00[11]	bDeviceRemovable	Indicates if the port has a removable device attached
8	0xFF[11]	bPortPwrCtrlMask	Required for compatibility with software written for 1.0 compliant devices

Note:

11. This value is configured through the External EEPROM.

9.0Configuration Options

Systems using CY7C656xx that do not have the fuse ROM pre-set at the factory must have an external EEPROM in order for the device to have a unique VID, PID, and DID. The CY7C656xx can communicate with SPI EEPROM that are either double byte addressed or a single byte with the 9th bit within the instruction byte, such as the 24LC040 parts use. The 25LC080 EEPROM uses the double byte address format, and therefore the CY7C656xx can communicate with these parts.

The '010s and '020s uses the same command format as used to interface with the ‘040 and hence these can also be used to interface with the CY7C656xx.

9.1Default – 0xD0 Load

When used in default mode, only a unique VID, PID, and DID must be present in the external SPI EEPROM. The contents of the EEPROM must contain this information in the following format:

Byte	Value
0	0xD0
1	VID (LSB)
2	VID (MSB)
3	PID (LSB)
4	PID (MSB)
5	reversed
6	DID (MSB)

Document #: 38-08037 Rev. *D Page 12 of 23