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changing clock configuration

Kasun Siriwardhana
Prodigy 105 points
Other Parts Discussed in Thread: TMS320F28069M

Dear TI team,

i am currently trying to build a code to run a display which has a HT1623 display driver with a TMS320F28069M MCU. I have built the code up to the point where the DATA pin (GPIO 7), CS pin (GPIO 5) and WR (GPIO 6) pin are sending the correct bit order. Even though, the display is not displaying any segment. 

The display previously worked perfectly with the Arduino Uno.

what can the matter be?

I am assuming that something is wrong with the clock configuration of the c2000 and the HT1623. 

THANK YOU!

  • 0
    TI__Guru* 80410 points

    Kasun,

    Is it possible to read back out the memory contents of the HT1623 to the C2000 to confirm the write happened correctly? 

    Keep in mind that C2000 has 3.3V level IOs, if HT supply voltage is 5V, this might present some issue with the read; the writes from MCU to HT should still be OK in since the VIL/VIH of the HT should be met.  Ideally we should have the devices powered the same though.

    wrt to the clock, you'll need to scale the GPIO high/low times to match the HT datasheet requirements.  I'm not sure the Arduino clock rates, but if you have this info, you could start with that scaling ratio in your code(assuming F2806x is running at 90MHz).

    Best,

    Matt

  • 0 in reply to MatthewPate
    Prodigy 105 points

    Matt

    The HT1623 is working with both 3.3V and 5V logic levels. Also we tried with a logic level shifter. 

    We scaled the clock to 16MHz(arduino clock rate) 

    Also we observed the output of 3 pins using a oscilloscope, how the signals look like. Then we matched with the signal output of c2000 MCU. They are nearly same.

    But we didn't see any output from the dispaly.

    What can I do for that?

    Thanks,

    Kasun

  • 0 in reply to Kasun Siriwardhana
    TI__Guru* 80410 points

    Kasun,

    If everything is matching, I'm not sure what the issue would be.  Have you tried to reach out to Holtek for support on their display?

    As I mentioned you could try to read data back out of the HT to the C2000 to verify you see the same data that was written.  That would at least tell you if the write from C2000 to HT happened correctly.  If you don't see the correct info, then you know that the write isn't latching the data in the HT correctly.

    This is just a general idea for debug, but could you try to write a smaller amount of data from the C2000 to the HT to see if you can observe any functionality on the HT?

  • 0 in reply to MatthewPate
    Prodigy 105 points

    MatthewPate,

    MatthewPate said:
    Have you tried to reach out to Holtek for support on their display?

    Not yet, that is the only option which I have now to do.

    MatthewPate said:
    but could you try to write a smaller amount of data from the C2000 to the HT to see if you can observe any functionality on the HT?

    Yes, I'm trying to turn on a segment only, not the multiple segments. But no output.

    I could be able to turn on the segments of display using Arduino board only.

    what should I do now?

    Thanks,

    Kasun

  • 0 in reply to Kasun Siriwardhana
    TI__Guru* 80410 points

    Kasun,

    I'm not familiar enough with this display to suggest the next debug steps, I think reaching out to Holtek is the right path forward.  Again, if the o-scope plots are identical from Arduino to C2000 I'm not sure why there would be an issue.  Have you verified that the voltage rails/reset/keep alive type circuits to the Holtek are correct as well?

    I may be mis-understanding the Holtek user guide, but there should be a way to read data back out of the display memory.  You could try this with the Arduino and then with C2000 to verify if the data you wrote is getting latched correctly.  That would 100% eliminate that as the issue if the contents are good.

    Best,

    Matthew