NXP Semiconductors LPC43 Series User Manual

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NXP Semiconductors LPC43 Series User Manual Manual pdf 552 page image

UM10503 All information provided in this document is subject to legal disclaimers. © NXP B.V. 2012. All rights reserved.User manual Rev. 1.3 — 6 July 2012 552 of 1269NXP Semiconductors UM10503Chapter 23: LPC43xx USB0 Host/Device/OTG controller23.8.1.6 Split state machinesThe start and complete split operational model differs from EHCI slightly because there isno bus medium between the EHCI controller and the embedded Transaction Translator.Where a start or complete-split operation would occur by requesting the split to the HShub, the start/complete split operation is simply an internal operation to the embeddedTransaction Translator. The following table summarizes the conditions where handshakesare emulated from internal state instead of actual handshakes to HS split bus traffic.23.8.1.7 Asynchronous Transaction scheduling and buffer managementThe following USB 2.0 specification items are implemented in the embedded TransactionTranslator:1. USB 2.0 specification, section 11.17.3: Sequencing is provided & a packet lengthestimator ensures no full-speed/low-speed packet babbles into SOF time.2. USB 2.0 specification, section 11.17.4: Transaction tracking for 2 data pipes.3. USB 2.0 specification, section 11.17.5: Clear_TT_Buffer capability provided thoughthe use of the TTCTRL register.23.8.1.8 Periodic Transaction scheduling and buffer managementThe following USB 2.0 specification items are implemented in the embedded TransactionTranslator:1. USB 2.0 specs, section 11.18.6.[1-2]:– Abort of pending start-splits:EOF (and not started in micro-frames 6)Idle for more than 4 micro-frames– Abort of pending complete-splits:EOFIdle for more than 4 micro-frames2. USB 2.0 specs, section 11.18.6.[7-8]:– Transaction tracking for up to 16 data pipes:– Complete-split transaction searching:Table 433. Split state machine propertiesCondition Emulate TT responseStart-split All asynchronous buffers full. NAKAll periodic buffers full. ERRSuccess for start of Async. Transaction. ACKStart Periodic Transaction. No Handshake (Ok)Complete-split Failed to find transaction in queue. Bus Time OutTransaction in Queue is Busy. NYETTransaction in Queue is Complete. [Actual Handshake fromLS/FS device]