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TLC59116 blinking period adjustment oddity

Rob'in
Prodigy 85 points
Other Parts Discussed in Thread: TLC59116, TLC59116F

Hello,

We are using a TLC59116 with an MSP430 as master. Everything works nicely except when we alternate the blinking period between 1s and 5s.

We use GRPFREQ to adjust the global blinking period (DMBLNK bit in MODE2 register set to 1). Often, when we write the value for the short period (1s) to GRPFREQ, the LEDs stop blinking for a few seconds before they start blinking at 1Hz.

The only reason we could see for this behavior is that some internal counter is not reset when GRPFREQ is changed to a lower value and this causes it to count to its maximal value (which corresponds to a period of ~10s) before it wraps. Our current work around is to perform an I2C bus software reset and reprogram the chips every time we have to decrease the blinking period; but that does not feel right...

Did someone already observe this behavior?

Are we doing something wrong?

Robin

  • 0
    TI__Guru 58215 points

    Hello Robin,

    We are working on follow up of your observation and will come back to you as soon as we have more detail.

    When you are going from 1s blinking to 5s blinking, is it a real issue that the blinking stops for a while and if yes, would you explain me why?

    Best regards,
    Brigitte

  • 0 in reply to Brigitte
    Prodigy 85 points

    Hello Brigitte,

    Thank you for your answer and for following up on our issue.

    To be more precise, we do not observe any problem when switching from 1s to 5s blinking periods, but we do when switching back from 5s to 1s. This why we suppose that when we decrease the value of the GRPFREQ register, we kind of jump backward over a counter which then counts to its maximum value before it wraps around.

    We consider this an issue because this switch from a long to a shorter blinking period follows a user action and it is supposed to give the user the indication that the system detected his action.

    Best regards,

    Robin

     

  • 0 in reply to Rob'in
    TI__Guru 58215 points

    Hello Robin,

    Maybe you could change the customer interaction the way to first turn on the LED and then change the blinking period? This would show the user that a change happened even if the blinking period is not correct for a short time.

    Best regards,
    Brigitte

  • 0 in reply to Brigitte
    Prodigy 85 points

    Hello Brigitte,

    Brigitte said:

    Maybe you could change the customer interaction the way to first turn on the LED and then change the blinking period? This would show the user that a change happened even if the blinking period is not correct for a short time.

    Thank you for the suggestion, unfortunately changing user requirements would be the last option to consider. However, as I already mentioned in my original message, we found a workaround to the issue we were facing. All other attempts we tried (mix of changing the GRPFREQ register with resetting the DMBLNK bit, ...) failed. So, I guess we will stay with our current software reset solution.

    Thank you very much for your support,

    Robin

  • 0 in reply to Rob'in
    TI__Guru 58215 points

    Hello Robin,

    Many thanks for the update.

    Best regards,
    Brigitte

  • 0 in reply to Brigitte
    Expert 1360 points

    Hi ,

    I am using TLC59116F led driver for my project and It's connected to MSP430FR series controller. I am using total of 10 led's connected to driver.

    My connection is as below,
    On LEDOUT-1 to LEDOUT-7 I have connected led's and on other port ( From LEDOUT-8 to LEDOUT-10) I have connected led's. 

    My Firmware Is as below,

    in MODE 1 register I am setting 0x01 value ( LED ALL CALL)

    in LEDOUT2(0x16h reg) I am setting as 0x55 .

    And then I am sending 0xff Value from Reg. PWM8- PWM15 ( My only 3 leds are in use from PWM8, PWM9 PWM10) .


    For other Channel I Have also Checked With This Value and configuration ( I.e, I have set all Individual LED's to 0xff Value). And they Are working fine with this configuration.


    My Problem is The only channel from PWM-8 (PWM8-PWM9-PWM10 for my application ) is not working . I have double checked Hardware and Connection as they are working,

    Can anyone suggest for this matter.

    Thanks,

  • 0 in reply to Hinesh Gohel
    TI__Expert 3460 points

    Hi Hinesh I can help you with this.

    Could you please email me both the schematic and code. I can be reached at h-kennedy@ti.com. It sounds like something minor with the code since all of the output channels are essentially the same.

  • 0 in reply to Harry Kennedy1
    Expert 1360 points
    Hi ,

    I have mailed you the code. And I have explained bit about the code.

    Waiting for your Replay,
    Thanks,
  • 0 in reply to Brigitte
    TI__Intellectual 2660 points

    Hi Brigitte,


    Can i say this is design limitation? When you change GRPFREQ to small value, there is a "reset counting" time.

    My customer do a breath function, and then change the GRPFREQ register value globally and periodic.
    But they saw the some led randomly late to turn on when GRPFREQ change to small value.

  • 0 in reply to kevin wu
    TI__Expert 3460 points

    Hi Kevin,

    Thanks for reaching out. We've recently been able to recreate the "reset counting" event that you are talking about. Currently, we suggest using the SW reset command before switching blinking frequencies in order to avoid this problem overall.

    If you would like to converse further about it, I can be reached at h-kennedy@ti.com

    Thanks!