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DLPC3479: Transition time to Standby Mode

Kazuyoshi Kawabe
Prodigy 30 points
Part Number: DLPC3479
Other Parts Discussed in Thread: DLP4710,

Hi Support team,

How long will it exactly take to switch to Standby Mode on DLPC3479 and DLP4710 system? I want to know the time from when the command is accepted to when the DMD starts to work at 50/50 refresh duty. 

Thanks

  • 0
    TI__Mastermind 20575 points

    Hi,

    Welcome to E2E and thank you for your interest in DLP!

    Can you share any documentation mentioning the standby mode you mention? There is a standby mode in DLPA300x LED drivers, but this is not accessible through external commands.

    Regards,

    Arthur

    . 

  • 0
    Prodigy 30 points

    Hi Arthur

    Thanks for your quick response. Please see "DLPC3479 Software Programmer's Guide". You can find Standby Mode in "3.2.1 Write Operating Mode Select(05h)" in page8 of this document.

    Thanks,

    Kazu 

  • 0 in reply to Kazuyoshi Kawabe
    TI__Mastermind 20575 points

    Hi Kazu,

    I measured the delay between the beginning of the I2C command and the beginning of standby mode. Delay is about 0.5 ms.

    Regards,

    Arthur

  • 0 in reply to Arthur Brown
    Prodigy 30 points

    Hi Arthur

    Thanks for your quick help. Can we assume that any transition to Standby Mode takes about 0.5ms of transition time? For example,  when I'm in Light Control – Internal Pattern Streaming Mode and then change the mode to Standby Mode, will it take about 0.5ms?

    Thanks,

    Kazu

  • 0 in reply to Kazuyoshi Kawabe
    TI__Mastermind 20575 points

    Hi Kazu, 

    I would assume similar time when transitioning from all modes.

    may i ask what your concern is regarding the transition time to standby mode?

    Regards,

    Arthur

  • 0 in reply to Arthur Brown
    Prodigy 30 points

    Hi Arthur,

    Thanks for your reply. The transition time affects the response time of the system. We care the response time. Can we also assume the transition time from Standby to Internal pattern streaming mode takes the same amount of time about 0.5ms?

    Thanks,

    Kawabe  

  • 0 in reply to Kazuyoshi Kawabe
    TI__Mastermind 20575 points

    Hi Kawabe,

    I would assume the chipset will wake up quickly into internal pattern mode. I cant comment on the exact time as this is tricky to measure. Let me talk to some people and see how this could be measured

    Regards,

    Arthur

  • 0 in reply to Arthur Brown
    Prodigy 30 points

    Hi Arthur,

    Thanks. We'll wait for your feedback.

    Best regards,

    Kazu

  • 0 in reply to Kazuyoshi Kawabe
    Prodigy 30 points

    Hi Arthur,

    Let me just confirm what you commented before. How long will it take from the beginning of Standby mode to the completion of entering Standby mode? I just wonder the meaning of " the beginning of standby mode" which makes me think that it have not entered into Standby mode yet.

    Thanks,

    Kazu

  • 0 in reply to Kazuyoshi Kawabe
    TI__Mastermind 20575 points

    Hi Kazu,

    I was measuring from the start of the I2C data to the point where the LEDs disable. In this case I believe the DMD has not yet began its 50/50 duty cycle. I think it will take a moment longer to start 50/50 duty cycle

    I have tried a few ways to measure this but nothing seems to work well - measuring when the LEDs disable is very easy, measuring the duty cycle of the DMD is quite a bit more tricky. 

    Thank you for your patience I am looking for a way to figure this out for you.

    Regards,

    Arthur

  • 0 in reply to Arthur Brown
    TI__Mastermind 28005 points

    Kazu-san,

    Is it correct to say that the most important functionality here is that the system can rapidly exit from standby mode for reliably operation?

    If that is the case, then the important factors to consider in this case are the the LED turn-on time and the embedded software response time. The LED turn-on time may or may not be relevant depending on the operating strength (current) that you have chosen for your LEDs. Meanwhile, the embedded software response time will encounter some minimum transition time out of standby mode, as well as a time duration required to load a sequence from EEPROM flash memory (depending on what mode you want to exit into). 

    Do you want to use internal pattern streaming or external pattern streaming? In either case you should measure the read time from the EEPROM flash device and the turn-on time of the leds to determine where the "bottleneck" is. In the case of external pattern streaming you will be forced to wait until the next VSYNC signal for any sequence activity to begin.

    It sounds like Arthur is investigating this for you and should get back with any additional information.

    Regards,

    Philippe

  • 0 in reply to Philippe Dollo
    Prodigy 30 points

    Hi Philippe-san,

    Thanks for your comment.

    What we really want to know is the time it takes to switch from Internal patten mode with Trigger-In enabled to Standby mode in which DMD operates at 50/50 duty cycle and  the time from Standby mode back to Internal pattern mode with Trigger-In enabled. Do you mean loading pattern sequence from flash will be required again when returning from Standby mode back to Internal patten mode with Trigger-In enabled even if it is loaded from flash once before?

    Best regards,

    Kazu 

  • 0 in reply to Kazuyoshi Kawabe
    TI__Mastermind 28005 points

    Kazu,

    Thanks for elaborating. I misunderstood your original question and believed you were asking about the time required to exit standby mode. In this case I would defer to Arthur's original answer.

    Regards,

    Philippe

  • +1 in reply to Kazuyoshi Kawabe
    TI__Mastermind 20575 points

    Kazu,

    From internal pattern mode going into standby -  from the beginning of the I2C communication to the beginning of 50/50 duty cycle on DMD is 2.2ms

    I then sent commands to go into internal pattern mode and immediately a command to run pattern once. from the beginning of the I2C communication to leave standby mode, to the illumination of the pattern is 16 ms. 

    Regards,

    Arthur

  • 0 in reply to Arthur Brown
    Prodigy 30 points

    Hi Arthur,Philippe,

  • 0 in reply to Kazuyoshi Kawabe
    Prodigy 30 points

    Hi Arthur,Philippe

    Thanks for your help.

    Best regards,

    Kazu

  • 0 in reply to Kazuyoshi Kawabe
    TI__Mastermind 28005 points

    Kazu,

    Not a problem. I'll mark this thread as resolved for now. If you have any new questions consider let us know.

    Regards,

    Philippe