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DAC81416EVM: How to use the toggle mode with a SUB2ANY and a DAC81416EVM？

user5624265
Prodigy 20 points

Part Number: DAC81416EVM

I read many times but still can not understand, how can i exactly use this toggle mode with USB2ANY and the EVM software? What is the AB-TOG[2:0] for? To write and load Registers or to replace the function of the TOGGLE[2:0]?

This is the first time I came into contact with this. I would appreciate it if you could answer this.

  • 0
    TI__Mastermind 19086 points

    Hi,

    Each DAC in the device can be independently configured to operate in toggle mode. A DAC channel in toggle mode incorporates two DAC registers (Register A and Register B) and can be set to switch repetitively between these two values. So when you enable those bits, corresponding DAC can be configured to toggle between those two values. This functionality can be used for adding dither to DAC output, or ON/OFF signaling etc.

    In EVM software , you can enable Toggle mode individually for each channels and configure the Register A and Register B.

    Let me know this answers your query and if you need more help regarding the same.

    Regards,

    AK

  • 0 in reply to Akhilesh K
    Prodigy 20 points

    Hi,

    Thank you very much for replying me. Let me change the question. What are the steps to use toggle mode? To follow the steps provided by TI like this?

    1. Set DAC channel in synchronous mode and disable toggle mode for that channel

    2. Write the desired Register A value to the DAC data register

    3. Issue a DAC trigger signal to load Register A

    4. Write the desired Register B value to the DAC data register

    5. Enable toggle mode to load Register B

    and what is the "DAC trigger signal" for? the LDAC bit?  and after doing these, should i turn on the DAC switch in High level in the software and connect the square wave signal to the TOGGLE pins？

    Besides, the same document mentions that :

    Additinally. the device can be configured for software contolled toggle operation by setting the SOFTTOGGLE-EN bit. In this mode, any of the three AB-TOG[2:0] bits can be used as a toggle control signal. Setting the AB-TOG bit to 1 enables Register B and dlearing it to 0 enables Register A.

    What are the detailed steps in this "SOFTTOGGLE" way?

    Thank you again for your time.

  • 0 in reply to user5624265
    TI__Mastermind 19086 points

    Hi,

    Toggled mode functionality explained in datasheet is correct as per your interpretation. For better clarity I will explain a bit more.

    DAC81416 has two registers, one is Data buffer ( called as Register B) and Register A. In normal synchronous mode of operation, data written using SPI frame will be first loaded into buffer register, after that DAC should receives LDAC signal (either hardware pin or software LDAC), contents of buffer register will be loaded into DAC register A and output will get updated. Now DAC Register A contains the data. This is normal synchronous operation.

    Now for toggle mode operation, you just disable first toggle mode operation of particular channel and follow the above steps.

    Additionally, after the LDAC trigger, you need to write the toggle DATA into register B and enable the toggle mode . Now Both registers contains different data and you can toggle between these two values based on either hardware toggle mode pins or software.

    Software toggle bits are mapped to hardware toggle pins. Those 3 bits are internally mapped to the hardware toggle mode pins. If you don't have extra GPIO's to control those toggle mode pins, you can enable the software toggle mode.

    Regards,

    AK