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SCD-20

Software and Drivers
Documentation
Specifications

20 Megabyte per second configurable DMA interface for SBus computers

The SCD-20 is a legacy product. Support for existing or newly-acquired boards can not be provided to anyone who did not have SCD-20 implementations that existed prior to the end of 2004.

Features

  • Transfer rates up to 20 MB per second.
  • 1 KByte FIFO
  • Implements a high speed DMA channel between an external device and Sun SPARCstation
  • RS-422 compatible driver/receivers
  • Customizable by a RAM based programmable gate array
  • Synchronous protocol
  • Clock timing from DMA interface, user device or both
  • Sun SPARCstation compatible
  • Device drivers for Solaris 1.x (SunOS 4.1.x) and Solaris 2.6+ (SunOS 5.x)
  • Single SBus slot

Description

The SCD-20 interface provides a high speed 16-bit parallel DMA channel between an external device and a Sun SPARCstation. The device interface uses RS422 compatible driver/receivers connected to a RAM based programmable gate array and 1 KByte FlFOs. The SCD-20 uses Direct Virtual Memory Access (DVMA) and asynchronous I/O to achieve transfer rates to or from memory of up to 20 MB per second. The hardware protocol is synchronous. That is, all data and control signals are sampled with a clock transmitted along with the data and control signals. This clock may be generated by the DMA interface or the user device or both. All signals are differential using RS422 specifications. The SCD-20 includes a versatile, straightforward protocol but optional customer-specific protocols may be developed.

Applications

  • Imaging devices
  • Scanners
  • Plotters
  • Research and development

Software

A standard SunOS loadable device driver for the SPARCstation is included with the SCD-20. The driver provides access to the SCD-20 through standard and asynchronous read and write system calls. Continuous transfers are implemented with asynchronous I/O.

    The SCD-20 is provided with minimal Codes PROM for identification only. User Code PROMS MAY be developed for specific applications.

Support

EDT provides several levels of customer support, from phone consultation to custom design of hardware, software, or FCode drivers, at hourly rates. Technical support is also provided though the Technical Support section of this web site.

Specifications

    SBus compliance

    DVMA master
    1, 2, 4, 8, or, 16 words per transfer - the largest accommodated by the host computer
    25 Mhz maximum clock
    Level 5 interrupt
    SBus memory space approximately 66K bytes

    Device interface

    Protocol:

    Synchronous streaming

    Buffers:

    1 KB FIFO for input 1 KB FIFO for output

    Connectors:

    AMP 787190-8 high-density 80-pin (mates with AMP 749621-8, backshell 749196-2)
    high density 80 pin

    Environmental

    Temperature:

    Operating: 10° to 40° C
    Nonoperating:-20° to 60° C

    Humidity:

    Operating: 20% to 80% noncondensing @ 40° C
    Nonoperating: 95% noncondensing @40° C

    Physical

    Single standard SBus slot
    Dimensions: 3.3" x 5.78" x 0.5"
    Weight: 3.5 oz.

    Power

    1.2A at 5 volts

    Software

    Software Drivers for Solaris 1.x (SunOS 4.1.x) and Solaris 2.x (SunOS 5.x)
    Standard read/write system call support
    Asynchronous l/O support for continuous transfers

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Engineering Design Team
1400 NW Compton Dr, Suite 315
Beaverton, OR 97006