ISP1130DL Philips Semiconductors, ISP1130DL Datasheet - Page 9

• Manufacturer Part Number: ISP1130DL
• Description: Universal Serial Bus compound hub with integrated keyboard controller
• Manufacturer: Philips Semiconductors

Philips Semiconductors
9397 750 06895
Objective specification
6.7 GoodLink
6.8 SoftConnect
Indication of a good USB connection is provided through GoodLink technology. An
LED can be directly connected via an external 330
GoodLink indication for the hub (upstream port) via output MEMSEL/UPGL and for
the two downstream ports via OCn/DPGLn, controlled via bits GL-MEMSELSelection
and EnableOverCurrent in the USBCON register (see
During enumeration the LED blinks on momentarily. After successful configuration of
the ISP1130, the LED is permanently on. The hub GoodLink indicator blinks off for
approximately 128 ms when the hub receives a packet addressed to it. Downstream
GoodLink indicators blink upon an acknowledgment from the associated port. In
‘suspend’ mode the LED is off.
This feature provides a user-friendly indication of the status of the hub, the connected
downstream devices and the USB traffic. It is a useful diagnostics tool to isolate faulty
USB equipment and helps to reduce field support and hotline costs.
The connection to the USB is accomplished by bringing D (for full-speed USB
devices) HIGH through a 1.5 k pull-up resistor. In the ISP1130, the 1.5 k pull-up
resistor is integrated on-chip and by default is disconnected from the +3.3 V supply.
The integrated microcontroller controls the connection of the internal resistor on D to
V
the Device Status register switches on V
pull-up resistor. A functional schematic diagram is given in
This mechanism allows the microcontroller to complete its initialization sequence
before deciding to establish connection to the USB. Re-initialization of the USB
connection can also be performed without disconnecting the cable.
It should be noted that the tolerance of the internal resistors is higher (30%) than is
specified by the USB specification (5%). However, the overall V
specification for the connection can still be met with good margin (see
decision to use this feature lies with the USB equipment designer.
idth
Fig 4. SoftConnect control logic.
pu(3.3)
via bit SoftConnect_N in the USBCON register (see
Rev. 01 — 23 March 2000
SoftConnect_N
(Device Status
(Configuration
Register)
Register)
Connect
USB compound hub with keyboard controller
ISP1130
pu(3.3)
(internal
pull-up)
1.5 k
supply
3.3 V
(default is off) to an alternative external
MGL920
resistor. The ISP1130 supports
Table
1.5 k
(external
pull-up)
V pu(3.3)
UP_DP
Figure
© Philips Electronics N.V. 2000. All rights reserved.
Table
53).
SE
53). Bit Connect in
4.
voltage
ISP1130
Table
92). The
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