CY7C656XX_11 CYPRESS [Cypress Semiconductor], CY7C656XX_11 Datasheet - Page 6

• Manufacturer Part Number: CY7C656XX_11
• Manufacturer: CYPRESS [Cypress Semiconductor]

Port Indicators
The USB 2.0 port indicators are also supported directly by
CY7C656xx. According to the specification, each downstream
port of the hub optionally supports a status indicator. The
presence of indicators for downstream facing ports is specified
by bit 7 of the wHubCharacteristics field of the hub class
descriptor. The default CY7C656xx descriptor specifies that port
indicators are supported (wHubCharacteristics, bit 7 is set). If
port indicators are not included in the hub, disable this bit through
EEPROM settings.
Each port indicator pin is strategically located directly on the
opposite edge of the port with which it is associated. A port
indicator provides two colors: green and amber. This is usually
implemented as two separate LEDs, one amber and the other
green. A combination of hardware and software control is used
to inform the user of the current status of the port or the device
attached to the port and to guide the user through problem
resolution. Colors and blinking provide information to the user.
The significance of the color of the LED depends on the
operational mode of CY7C656xx. The CY7C656xx port
indicators has two modes of operation: automatic and manual.
On power up the CY7C656xx defaults to automatic mode, where
the color of the Port Indicator (green, amber, off) indicates the
functional status of the CY7C656xx port. In automatic mode, the
CY7C656xx turns on the green LED whenever the port is
enabled and the amber LED when an overcurrent condition is
detected. The color of the port indicator is set by the port state
machine. Blinking of the LEDs is not supported in automatic
mode.
automatic mode.
Document Number: 38-08037 Rev. *S
Note
1. Information presented in
Table 1
identifies the mapping of color to port state in
Table 1
and
Table 2
is from USB 2.0 specification Tables 11-6 and 11-7, respectively.
Table 1. Automatic Port State to Port Indicator Color
Mapping
The LED control lines can also be modulated with a square wave
for power conservation. The polarity of these pins is
programmable, see
In manual mode, the indicators are under the control of the host,
which can turn on the LEDs, or leave them off. This is done by a
USB Hub class request. Blinking of the LEDs is supported in
manual mode. The port indicators enable the user to intervene
in any error detection. For example, when babble is detected
while plugging in a defective device, or when an overcurrent
condition occurs, the port indicators corresponding to the
downstream port blink green or only light the amber LED,
respectively.
Table 2
CY7C656xx is in manual mode.
Table 2. Port Indicator Color Definitions in Manual Mode
Off or Amber, if due to an
overcurrent condition
Off
Green
Off
Off
Amber
Green
Blinking Off / Green
Blinking Off / Amber
Blinking Green / Amber
Color Definition
Color Definition
displays the color definition of the indicators when
Downstream Facing Hub Port State
Configuration Options on page
[1]
Powered Off
Disconnected, Disabled, Not
Configured, Resetting, Testing
Enabled, Transmit, or
TransmitR
Suspended, Resuming,
SendEOR, Restart_E/S
Not operational
Error condition
Fully operational
Software attention
Hardware attention
Reserved
Port State
Port State
CY7C656xx
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