isp1520 NXP Semiconductors, isp1520 Datasheet - Page 8

• Manufacturer Part Number: isp1520
• Description: Hi-speed Universal Serial Bus Hub Controller
• Manufacturer: NXP Semiconductors

Philips Semiconductors
7. Functional description
ISP1520_4
Product data sheet
7.2.1 Philips serial interface engine
7.2.2 Routing logic
7.2.3 Transaction translator
7.2.4 Mini-Host Controller
7.1 Analog transceivers
7.2 Hub controller core
The integrated transceivers directly interface to USB lines. They can transmit and receive
serial data at high-speed (480 Mbit/s), full-speed (12 Mbit/s) and low-speed (1.5 Mbit/s).
The main components of the hub core are:
The Philips Serial Interface Engine (SIE) implements the full USB protocol layer. It is
completely hardwired for speed and needs no firmware intervention. The functions of this
block include: synchronization, pattern recognition, parallel or serial conversion, bit
(de-)stuffing, CRC checking and generation, Packet IDentifier (PID) verification and
generation, address recognition, and handshake evaluation and generation.
The routing logic directs signaling to appropriate modules (mini-Host Controller, Original
USB repeater and Hi-Speed USB repeater) according to the topology in which the hub is
placed.
The Transaction Translator (TT) acts as a go-between mechanism that links devices
operating in Original USB mode and Hi-Speed USB upstream mode. For the ‘IN’ direction,
data is concatenated in TT buffers till the proper length is reached, before the host takes
the transaction. In the reverse direction (OUT), the mini-host dispenses the data
contained in TT buffers over a period that fits into the Original USB bandwidth. This
continues until all outgoing data is emptied. TT buffers are used only on split transactions.
The internal mini-host generates all the Original USB IN, OUT or SETUP tokens for the
downstream facing ports, while the upstream facing port is in high-speed mode. The
responses from Original USB devices are collected in TT buffers, until the end of the
complete split transaction clears TT buffers.
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Philips Serial Interface Engine (SIE)
Routing logic
Transaction Translator (TT)
Mini-Host Controller
Hub repeater
Hub controller
Port controller
Bit clock recovery
Rev. 04 — 28 April 2006
© Koninklijke Philips Electronics N.V. 2006. All rights reserved.
Hi-Speed USB hub controller
ISP1520
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