Cypress EZ-USB HX2LP - Manual (Page 12)

CY7C656xx PRELIMINARY
Document #: 38-08037 Rev. *D Page 12 of 23
8.8 Hub Descriptor
9.0 Configuration 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.
9.1 Default – 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 All Speed Field Name Description
0 0x09 bLength 9 Bytes
1 0x29 bDescriptorType HUB Descriptor
2 0x04
[11]
0x02
bNbrPorts Number of ports supported, CY7C65640B or CY7C65630.
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]
0xAE
[11]
bHubContrCurrent Maximum current requirement for the Hub Controller at full-speed.
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.
Byte Value
0 0xD0
1 VID (LSB)
2 VID (MSB)
3 PID (LSB)
4 PID (MSB)
5 reversed
6 DID (MSB)