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NS9750 - Training Hardware

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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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usb device
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

USB Device Hardware Configuration


DMA Setup/Completion

Handle Transaction Errors

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)
dma setup completion
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
handle transaction errors
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)
transaction error
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 ???
usb host
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
usb host operation

USB Host Operation

Initialize OHCI

Wait for devices to attach

Transfer Descriptor Setup/Complete

ohci initialization
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)
ohci setup
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
wait for device to attach
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
transfer descriptor setup complete
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.
hints kinks
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.