ISP1507D1HNUM STEricsson, ISP1507D1HNUM Datasheet - Page 43

• Manufacturer Part Number: ISP1507D1HNUM
• Manufacturer: STEricsson

Specifications of ISP1507D1HNUM

• Lead Free Status / RoHS Status: Compliant

CD00269906
Product data sheet
10.14 Aborting transfers
10.15 Avoiding contention on the ULPI data bus
The ISP1507D1 supports aborting transfers on the ULPI bus. For details, refer to UTMI+
Low Pin Interface (ULPI) Specification Rev. 1.1, Section 3.8.4.
Because the ULPI data bus is bidirectional, avoid situations in which both the link and the
PHY simultaneously drive the data bus.
The following points must be considered while implementing the data bus drive control on
the link.
After power-up and clock stabilization, default states are as follows:
When the ISP1507D1 wants to take control of the data bus to initiate a data transfer, it
changes the DIR value from LOW to HIGH.
At this point, the link must disable its output buffers. This must be as fast as possible so
the link must use a combinational path from DIR.
The ISP1507D1 will not immediately enable its output buffers, but will delay the enabling
of its buffers until the next clock edge, avoiding bus contention.
When the data transfer is no longer required by the ISP1507D1, it changes DIR from
HIGH to LOW and starts to immediately turn off its output drivers. The link senses the
change of DIR from HIGH to LOW, but delays enabling its output buffers for one CLOCK
cycle, avoiding data bus contention.
•
•
•
The ISP1507D1 drives DIR to LOW.
The data bus is input to the ISP1507D1.
The ULPI link data bus is output, with all data bus lines driven to LOW.
Rev. 03 — 28 July 2010
ULPI HS USB host and peripheral transceiver
ISP1507D1
© ST-ERICSSON 2010. All rights reserved.
43 of 73