• State
  • Locked Locked
  • Replies 3 replies
  • Subscribers 46 subscribers
  • Views 495 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.

DAC8760 Programmable Slew Rate

Isao Takigasaki
Expert 3360 points
Other Parts Discussed in Thread: DAC8760

My customer can't write any code to data register of DAC8760 with setting programmable slew rate register. PLS give them any advise to solve it. The procedure to write the code is shown in below.

 

 

1. Set reset register to 1.

2. Wait 1ms.

3. Write 0x7000 or 0x0000 to configulation register.

4. Write 0x1011 to control register. SREN is set to 1 in this step.

5. Write 0x2AAA or 0x1999 to data register.

6. Read back status register after waiting for a while. The status register value is 0x0004 or 0x0000. It means SR_EN is not 1.

7. Read back data register. The code is 0x000c. It's not wirtten value in step 5 in above. It should be 0x2AAA or 0x1999.

  • 0
    TI__Genius 11750 points

    Howdy Takigasaki-san,

    I'll use this information to try to replicate this issue in our labs.  I'll update this post once I once I analyze our findings. I understand the urgency and appreciate your patience.

    Best Regards,

    Matt

  • 0 in reply to Matthew Sauceda
    TI__Expert 3360 points

    Hi, Matt-san

    Thank you for your cooperation.
    I will wait the result.  I also ask my customer to take some oscilloscope capture of SPI communication tomorrow. 

    Best Regards, Taki

  • 0 in reply to Isao Takigasaki
    TI__Genius 11750 points

    Hi Takigasaki-san,


    We tried to replicate this issue on an EVM but we were unsuccessful. There are a few questions that I was hoping you could help answer.

    • The values written to the control register confirm that this part is set for voltage mode, set to a 10V Range. Is it correct to state that the wanted mode is voltage and not current? Please have the customer verify range settings by reviewing Table 9 of the datasheet.
    • The SR_EN is only "1" when the device is actively slewing. One way to verify the functionality of the slew bits is to program the SRCLK to the lowest update speed, with a single LSB step size (programmed through SRSTEP). You will be able to verify the slow update rate of Vout, and verify that the SR_EN bit sets to '1'. Once the programmed voltage is achieved the SR_EN bit clears to '0'.
    • The code 0x0004 implies an IOUT Fault. I'm unsure of the load attached to the voltage output, is this something you can share through schematics?
    • Can the customer repeat the steps in the original post and perform a read-back after each step?

    I appreciate your help in obtaining the answers and look forward to more information that will give us more insight into the customer's issue.


    Best Regards,
    Matthew Sauceda