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CCS/DAC7811EVM: CC1310 and DAC7811EVM Communication Problem

Part Number: DAC7811EVM
Other Parts Discussed in Thread: CC1310, , DAC7811

Tool/software: Code Composer Studio

Hi,

I would like to use CC1310 Launchpad by the SPI interface,

giving the command and digital data to DAC7811EVM.

And getting the output analog result from the DAC7811EVM.

 

This is the scope capture, and the connection is following by:

       Ch1: MOSI (DAC7811: J2_T pin11, CC1310: DIO9)

       Ch2: SCLK (DAC7811: J2_T pin3, CC1310: DIO10)

       Ch3: SYNC (DAC7811: J2_T pin7, CC1310: DIO15)

       Ch4: Vout (DAC7811: TP2)(DAC7811: AGND)

I modified from CC1310 example code "spimaster_CC1310_LAUNCHXL_tirtos_css".

So I put the "Board_SPI_MASTER_READY"(DIO15) to be my "SYNC" pin. (I'm not sure is it feasibility or not..)

I just doing for testing, so I used the "dupont Line" cross over the CC1310 to DAC7811EVM.

The wire i connected is following:

       3.3V, Gnd ---to---> J3 pin10, pin5 (from CC1310)

       +5V, -5V, Gnd ---to---> J3 pin3, pin4, pin6

       +10V, 0V ---to---> J3 pin1 and pin2,

(The jumper or switch on DAC7811EVM were all in default)

In the SPI master(CC1310), I wrote in Txbuffer :

       Txbuffer[0]=0x1800

       Txbuffer[1]=0x1C00 

And the SPI bit rate i used with 4Mbps.

By all of these setting, I always got nothing to my output from DAC7811 TP2.

Please help me in rectifying the issue.

Truly needed for someone's help.

Best Regard

  • Hi Victor,

    Thank you for your query. I am looking into your issue. I will get back by tomorrow.

    Regards,
    Uttam Sahu
    Applications Engineer, Precision DACs
  • Hi Victor,

    Looks like the MOSI line isn't connected or is loaded. Could you get a fresh scope capture after fixing the issue with MOSI?

    Regards,
    Uttam
  • Hi Uttam,

    This time, I change the CC1310 to Arduino.(shown in the scope picture)

    So it means that the MOSI was connected for sure.

    And this time, the only different part of it is i gave ±10V to Vcc&Vss(J3 pin1 and pin2).

    but no matter what the MOSI data i gave, the Vout always output the 4.3V(shown down of the picture)

    I had even try many SPI data rate, but nothing change.

    I think i need to confirm that which pin should be connected.

    Can you just list for it or give me some recommendation.

    The most confused part was in the DAC7811EVM J3 part.

    I'm not sure how many external power should I gave for it.

    Best Regards,
    Victor

  • Hi Victor,

    The data is sampled on the falling edge of the SCLK. On your scope shot, it looks like the data is sent at the rising edge. You have selected mode 2 of SPI. Can you use mode 1 and check?

    I also noticed that you have connected MOSI to SDO (J2-T.pin11). Instead, it should be connected to SDI (J2-B.pin11).

    The VCC/VSS connection is fine.

    Please let me know if the above changes resolve the issue or not.

    Regards,
    Uttam
  • I change J2-T.pin11 to J2-B.pin11.
    and it works!!!!
    Thanks very much!!!!

    Best Regards,
    Victor
  • Sorry for bother again.

    After all the setting from I said before, I got this follow result.

    I toggle 0x1000 and 0x1FFF to be the SPI MOSI data.

    The sky blue curve was analog output from DAC7811 TP2.

    I found that the DAC settling time(update time) was really long, and It almost 17.45us.

    Is that any way I could try to reduce this settling time?

    Best Regards,
    Victor

  • Hi Victor,

    It might be somewhere set in the controller. are you facing this issue on your design as well?

    Regards,

    Uttam

  • Do you have an update on this?

    Regards,

    Uttam