USBProtocolTest.ppt

Here is a complete In Transaction with the Link Commands – shown - On the Bulk in transaction – host always starts by sending ACK TP – equivalent of the In Token in USB 2.0 . The Lgood is sent to ACK all header packets – both DPH and TP packets - here comes payload – Host sends Lgood to ack HP and then TP ACK To ackknowledge the data payload. This SeqNum of 25 implicitly acknowledges this HP 24. * This is a setup transaction with a CRC error in a transaction packet – in this case the retry is initiated by the link layer. The Host start by sending DPH and DP 8 byte payload – Lgood from the device. Sends TP ACK to acknowledgement with CRC – host responds with LBAD – did not receive - Device RTRY command = the ACK recent with Lgood. * Retry sending HP – after that go to recovery * * * * There are lot of challenges – these only some of key issues Frequent entry into low power modes – aggravates signal lock issue. Because the link retrains when moving through recovery * * There are lot of challenges – these only some of key issues Frequent entry into low power modes – aggravates signal lock issue. Because the link retrains when moving through recovery * * There are lot of challenges – these only some of key issues Frequent entry into low power modes – aggravates signal lock issue. Because the link retrains when moving through recovery * * * * The burden on test equipment is significantly higher compared with 2.0 - Testing at the logical link and protocol layers requires inserting analysis tools in the line while having minimal effect on the signal – the analysis tool can not be an active node in the network – it can not alter the behavior of the link layer in any way. – With USB 3.0 not only is there a lot data on the wire -there’s nearly a constant flow of ordered sets -on the line all which need to be accurately captured and decoded. * * The burden on test equipment is significantly higher compared with 2.0 - Testing at the logical link and protocol