• State Resolved
  • Locked Locked
  • Replies 4 replies
  • Subscribers 63 subscribers
  • Views 467 views
  • Users 0 members are here
Support feedback
Options
Options
Related

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

TLC 5927 multiple devices

phil crescenzo
Prodigy 150 points
Other Parts Discussed in Thread: TLC5917, TLC5927

I am designing an IR touch screen and I was considering using the 5927 to control the LEDs. I want to be able to turn on one at  a time or specific groups of LEDs.Can I do that with the 5927?

I am unsure how the cascading works with the serial interface when you are using more than one device. Are there any more docs or examples that explain this in detail?

Thanks!

  • 0
    TI__Genius 14890 points

    Phil,

    The TLC5927 acts just like a shift register.  Nothing makes it to the outputs until they are latched in.  If you have multiple TLC5927 drivers, it just makes a bigger shift register.  SDO of one device is the SDI of the next.  Nothing is sent to the outputs until latched in.  As a result, you can change from 1 to all channels at the same time - and anything in between.  A simple diagram is included in the TLC5917 (8-channel version of the TLC5927).  Please view figure 17 on page 19.

    If you need more information on any aspect, we can help you out.

    Regards,

    Dick

  • 0 in reply to Dick Stacey
    Prodigy 150 points

    Thanks Dick..

    So then we read the error data from the SDO of the last device as well I suppose.  Sounds good. Thank you.

  • 0 in reply to phil crescenzo
    TI__Genius 14890 points

    Exactly.  When you get into error mode, the device takes the error register for each device and puts it into the shift register.  Then each device shifts out the error information in the same method as normal input.  Note that when you shift the error log out, you are shifting in new data.  Additionally, you do not disturb the data in the output buffers (the channels remain in the on or off state as you programmed originally).  You can use dummy data or new data.  Nothing happens until you latch again.

  • 0 in reply to Dick Stacey
    Prodigy 150 points

    Ok thank you very much for the prompt answers. Very helpful. AND for the reminder that I am shifting new data in when I read the error.