CY7C656XX CYPRESS [Cypress Semiconductor], CY7C656XX Datasheet - Page 4

• Manufacturer Part Number: CY7C656XX
• Manufacturer: CYPRESS [Cypress Semiconductor]

Document #: 38-08037 Rev. *H
this port is forwarded to the host. The host may resume the
port by sending a ClearPortSuspend command.
Upstream Port
The upstream port includes the transmitter and the receiver
state machine. The transmitter and receiver operate in high
speed and full speed depending on the current hub configu-
ration.
The transmitter state machine monitors the upstream facing
port while the Hub Repeater has connectivity in the upstream
direction. This machine prevents babble and disconnect
events on the downstream facing ports of this hub from propa-
gating and causing the hub to be disabled or disconnected by
the hub to which it is attached.
Power Switching
The CY7C656xx includes interface signals for external port
power switches. Both ganged and individual (per-port) config-
urations are supported, with individual switching being the
default. Initially all ports are unpowered. After enumerating,
the host may power each port by sending a SetPortPower
request for that port. The power switching and over-current
detection of downstream ports is managed by control pins
connected to an external power switch device. PWR [n]#
output pins of the CY7C656xx series are connected to the
respective external power switch's port power enable signals.
(Note that each port power output pin of the external power
switch must be bypassed with an electrolytic or tantalum
capacitor as required by the USB specification. These capac-
itors supply the inrush currents, which occur during
downstream device hot-attach events.) The polarity of this pin
can be configured through the EEPROM; see
page
Overcurrent Detection
Overcurrent detection includes 8 ms of timed filtering by
default. This parameter is configured from the external
EEPROM in a range of 0 ms to 15 ms for both enabled ports
and disabled ports individually. Detection of over-current on
downstream ports is managed by control pins connected to an
external power switch device.
Table 1. Automatic Port State to Port Indicator Color Mapping
Off or Amber, if due to an
Overcurrent Condition
13.
Powered Off
Not Configured, Resetting, Testing
Off
Disconnected, Disabled,
Downstream Facing Hub Port State
“0xD4 Load” on
The OVR[n]# pins of the CY7C656xx series are connected to
the respective external power switch's port over-current
indication (output) signals. Upon detecting an over-current
condition, the hub reports the overcurrent condition to the host
and disables the PWR# output to the external power device.
The polarity of the OVR pins can be configured through the
EEPROM; see
Port Indicators
The USB 2.0 port indicators are also supported directly by the
CY7C656xx. In accordance with 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 (wHubCharacter-
istics, 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 opera-
tional mode of the CY7C656xx. There are two modes of
operation for the CY7C656xx port indicators: 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.
mapping of color to port state in automatic mode.
Green
Enabled, Transmit, or
TransmitR
“0xD4 Load” on page
Off
Suspended, Resuming,
SendEOR, Restart_E/S
13.
Table 1
CY7C656xx
Page 4 of 24
identifies the
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