ISP1521 datasheet(11/53 Pages) PHILIPS

11 / 53 page

Philips Semiconductors

ISP1521

Hi-Speed USB hub controller

Product data

Rev. 03 — 24 November 2004

11 of 53

9397 750 13702

8.2.5

Hub repeater

A hub repeater is responsible for managing connectivity on a per packet basis. It

implements packet signaling connectivity and resume connectivity. There are two

repeaters in the ISP1521: a Hi-Speed USB repeater and an Original USB repeater.

The only major difference between these two repeaters is the speed at which they

operate. When the hub is connected to an Original USB system, it automatically

switches itself to function as a pure Original USB hub.

8.2.6

Hub and port controllers

The hub controller provides status report. The port controller provides control for

individual downstream facing port; it controls the port routing module. Any port status

change will be reported to the host via the hub status change (interrupt) endpoint.

8.2.7

Bit clock recovery

The bit clock recovery circuit extracts the clock from the incoming USB data stream.

8.3 Phase-locked loop clock multiplier

A 12 MHz to 480 MHz clock multiplier PLL is integrated on-chip. This allows the use

of low-cost 12 MHz crystals. The low crystal frequency also minimizes

ElectroMagnetic Interference (EMI). No external components are required for the

operation of the PLL.

8.4 I2C-bus controller

A simple serial I2C-bus interface is provided to transfer vendor ID, product ID and

string descriptor from an external I2C-bus EEPROM (for example, Philips PCF8582 or

equivalent) or microcontroller. A master/slave I2C-bus protocol is implemented

according to the timing requirements as mentioned in the I2C-bus standard

speciﬁcations. The maximum data count during I2C-bus transfers for the ISP1521 is

256 bytes.

8.5 Overcurrent detection circuit

An overcurrent detection circuit is integrated on-chip. The main features of this circuit

are: self reporting, automatic resetting, low-trip time and low cost. This circuit offers

an easy solution at no extra hardware cost on the board.

8.6 GoodLink

Indication of a good USB connection is provided through GoodLink technology. An

LED can be directly connected to pin HUBGL_N via an external 330

Ω resistor.

During enumeration, the LED blinks on momentarily. After successful conﬁguration,

the LED blinks off for 100 ms upon each transaction.

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.

8.7 Power-on reset

The ISP1521 has an internal Power-On Reset (POR) circuit.

ISP1521 Datasheet(PDF) 11 Page - NXP Semiconductors

ISP1521 Datasheet(HTML) 11 Page - NXP Semiconductors

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53

Datasheet Download

Link URL