• Join
  • Sign In with my.TI Login
Texas Instruments
  • Products
  • Applications
  • Tools & Software
  • Support & Community
  • Sample & Buy
  • About TI
Sample & Purchase Cart Sample & Purchase Cart
  • Search
  • Advanced
TI E2E™ Community
  • Support Forums
  • Blogs
  • Groups
  • Videos
  • 简体中文
  • More ...
TI Home » TI E2E Community » Support Forums » Data Converters » Precision Data Converters » Precision Data Converters Forum » LMP90100 - Connecting 2 devices that are not isolated to the same SPI port
Share
Precision Data Converters
  • Forum
  • Files
  • E2E Wiki
Options
  • Subscribe via RSS
Check out
The Signal blog
  • $core_v2_blog.Current.Name

    Grounding Principles

    Posted 2 days ago
    by Bruce Trump
    In a previous blog on supply bypassing , I cautioned that poor...
  • $core_v2_blog.Current.Name

    Handy Gadgets and Resistor Divider Calculations

    Posted 10 days ago
    by Bruce Trump
    Handy gadgets make our engineering life easier—the little...
  • $core_v2_blog.Current.Name

    Chopper Op Amps—are they really noisy?

    Posted 17 days ago
    by Bruce Trump
    Chopper op amps offer very low offset voltage and dramatically...

Forums

LMP90100 - Connecting 2 devices that are not isolated to the same SPI port

This question is answered
EngH060
Posted by EngH060
on Jul 31 2012 15:47 PM
Prodigy100 points

Can you recommend the best way to connect 2 LMP90100 devices to the same SPI port?  There is an E2E post that involves doing this but the devices in that case are electrically isolated.  The guidance offered there does not help in my case where isolation is not used.  It seems some gating will be necessary to separate the DRDYB of each from the port SDO pin.   A recommendation would be greatly appreciated.

Related, some SPI devices can operate in a cascade mode where SDO of device 1 can connect to SDI of device 2 and the devices act as one long data chain.  This would be a very useful mode in my case but I do not believe this is supported by the LMP90100.  Please confirm.  A few more connection diagrams in the data sheet would be very helpful.

Report Abuse
  • Reply
You have posted to a forum that requires a moderator to approve posts before they are publicly available.
All Replies
  • Tom Hendrick
    Posted by Tom Hendrick
    on Jul 31 2012 20:43 PM
    Verified Answer
    Verified by EngH060
    Guru86210 points

    Hi EngH60,

    On running two LMP90100's from the same SPI bus, I believe you are referring to this post:

    http://e2e.ti.com/support/data_converters/precision_data_converters/f/73/p/199744/711554.aspx#711554

    Not sure if you noticed but Asutosh and Javier had different issues (but both are in the same thread) - one was optically isolated and the other was not.  If you read the parts of that post related to Javier, did Murali cover your question?

     

    Regards,

    Tom

    Report Abuse
    • Reply
    You have posted to a forum that requires a moderator to approve posts before they are publicly available.
  • Murali Srinivasa
    Posted by Murali Srinivasa
    on Aug 01 2012 03:04 AM
    Verified Answer
    Verified by EngH060
    Intellectual1060 points

    Hi,

    For connecting multiple LMP90100 to one SPI port of the MCU, there is no special programming needed for LMP90100. Care has to be taken to avoid asserting CSB's of both the LMP90100 together in the default condition. However there are various modes of the SDO driver which can be selected based on the application requirements.

      

    Daisy chaining is not supported in LMP90100.

    Regards,
    Murali 

    Report Abuse
    • Reply
    You have posted to a forum that requires a moderator to approve posts before they are publicly available.
TI E2E™ Community
  • Support Forums
  • Blogs
  • Videos
  • Groups
  • Site Support & Feedback
  • Settings
TI E2E™ Community Groups
  • TI University Program
  • Make the Switch
  • Microcontroller Projects
  • Motor Drive & Control
Other Communities
  • Deyisupport
  • Designsomething.org
  • beagleboard.org
  • TI on Element 14
  • TI on TechXchangeSM
Other Technical & Support Resources
  • WEBENCH® Design Center
  • Product Information Centers
  • Technical Documents
  • TI Design Network
  • TI Technical Articles
  • TI Training

All content and materials on this site are provided "as is". TI and its respective suppliers and providers of content make no representations about the suitability of these materials for any purpose and disclaim all warranties and conditions with regard to these materials, including but not limited to all implied warranties and conditions of merchantability, fitness for a particular purpose, title and non-infringement of any third party intellectual property right. TI and its respective suppliers and providers of content make no representations about the suitability of these materials for any purpose and disclaim all warranties and conditions with respect to these materials. No license, either express or implied, by estoppel or otherwise, is granted by TI. Use of the information on this site may require a license from a third party, or a license from TI.

Content on this site may contain or be subject to specific guidelines or limitations on use. All postings and use of the content on this site are subject to the Terms of Use of the site; third parties using this content agree to abide by any limitations or guidelines and to comply with the Terms of Use of this site. TI, its suppliers and providers of content reserve the right to make corrections, deletions, modifications, enhancements, improvements and other changes to the content and materials, its products, programs and services at any time or to move or discontinue any content, products, programs, or services without notice.

Follow Us Texas Instruments on Facebook Texas Instruments on Twitter Texas Instruments on LinkedIn Texas Instruments on Google+
TI Worldwide | Contact Us | my.TI Login | Site Map | Corporate Citizenship | mobile m.ti.com (Mobile Version)

TI is a global semiconductor design and manufacturing company. Innovate with 100,000+ analog ICs and
embedded processors, along with software, tools and the industry’s largest sales/support staff.

© Copyright 1995-2013 Texas Instruments Incorporated. All rights reserved.
Trademarks | Privacy Policy | Terms of Use