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NS9750 - Training Hardware

NS9750 - Training Hardware. USB 2.0. USB Overview. USB Device. Full Speed (12Mbps) or Low Speed (1.5Mbps) One bi-directional control EP (end point) and 11 unidirectional programmable EP’s Supported by a DMA controller Select either Usb Host or Device. USB Device Hardware Configuration.

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NS9750 - Training Hardware

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  1. NS9750 - Training Hardware

  2. USB 2.0

  3. USB Overview

  4. USB Device • Full Speed (12Mbps) or Low Speed (1.5Mbps) • One bi-directional control EP (end point) and 11 unidirectional programmable EP’s • Supported by a DMA controller • Select either Usb Host or Device

  5. USB Device Hardware Configuration Negotiate/Configure DMA Setup/Completion Handle Transaction Errors

  6. Negotiate/Configure • Respond to Get Device Configuration Setup Command (see www.usb.org/developers/docs) • Device HW Naks until an IN DMA on Channel zero is created • After Set Device Configuration Setup Command interrupt occurs, read CFG, INTF, and ALT (0x9010_0004) and program endpoint registers (0x9010_3000 - 0x9010_3150)

  7. DMA Setup/Completion • Enable DMA In or Out depending on CIA selected by Usb Host • Fifo/DMA 0 is OUT on Control port, DMA 1 is IN, remainder correspond to Endpoints 1..11 • Enable DMA completion and error interrupts for each channel [GLBL_EN, GBL_DMA, FIFO, URST, ERR(0-2), NAK(0-2), UFLOW(0-2), OFLOW(0-2)] • Ack interrupt complete by writing ECIP of interrupt status register

  8. Handle Transaction Errors • Read ECIP to determine if error occurred. • If error on IN DMA (to host): • Read in packet counter PKTCNT • Increment DMA start pointer by that many packets (start += PKTCNT * MAXPKTSZ), and decrement length by that amount • Write buffer REFETCH bit • Take the channel/Fifo out of reset (write status.CLR to 0)

  9. Transaction error • If OUT DMA Error: • NS9750 will close all outstanding DMA buffers on this channel (with error) • User should read PKTCNT and setup a new DMA buffer starting at PKTCNT+MAXPKTSZ (since PKTCNT –1 ok transactions) • ??Take channel Fifo out of reset ???

  10. USB Host • Follows OHCI 1.0a programming model • See www.usb.org/developers/docs • Compatible with Full and low speed devices • Provides current relay pin for power management of connected device

  11. USB Host Operation Initialize OHCI Wait for devices to attach Transfer Descriptor Setup/Complete

  12. OHCI Initialization • Wait for NS9750 UsbHost to come out of reset • Allocate an HCCA structure • Create blank TD and ED for Bulk, Isochronous, Interrupt and Control queues • Enable OHCI interrupt in NS9750 • Set FrameInterval and HcPeriodic Start • Set up Root Hub (eg GoodToGo, PowerSwitching and OverCurrentProtection)

  13. OHCI Setup • Host Controller Registers start at 0x0900_1000 • User must set up HCCA and maintain Endpoint descriptors and Transfer Descriptors • Only one interrupt: OHCI_IRQ

  14. Wait for device to attach • Standard OHCI, wait for port CCS, then reset the attached device, then start GET DEVICE DESCRIPTOR transfer. • Application sends above transfer and then sends a SET CONIFGURATION and SET INTERFACE transfer. • From the selected CIA, add Endpoint descriptors to appropriate OCHI schedule table

  15. Transfer Descriptor Setup/Complete • Follows standard OCHI model • Setup TDs as requested by app. • Handle Done queue interrupts to retire TDs and free TD memory.

  16. Hints & Kinks • Can the USB Host and Device work at the same time? • No • Are Usb 2.0 Devices supported? • USB 2.0 Low and Full speed devices are. In addition, USB 1.1 devices are supported. • Does the USB Host supply power? • Not from the NS9750.

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