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Original question:

DAC8760: Questions about daisy-chain of DAC8760.

DAC8760: Daisy chain mode

HS FAE Germany
Mastermind 32190 points
Part Number: DAC8760
Other Parts Discussed in Thread: DAC8775

Hello,
my customer is using daisy chain mode and sees also problems in their application. He recognized that the d/s was changed and the daisy chain mode removed. He is already in production and need the daisy chain mode because he doesn't have any pins left in the MCU. I saw this E2E:

https://e2e.ti.com/support/data-converters-group/data-converters/f/data-converters-forum/1074345/dac8760-questions-about-daisy-chain-of-dac8760?tisearch=e2e-sitesearch&keymatch=DAC8760%20daisy#

- What would be a workaround to have stable operation in the daisy chain mode? May be in the SW of the MCU?
- Is the DAC8760 running stable if the CRC and watchdog mode is not used?
- Is there any alternative part which he can use instead of DAC8760?

Regards, Holger

  • 0
    TI__Guru* 97465 points

    Holger,


    For your customer, you had mentioned that they see problems with the application. Do these problems line up with the ones in the post you mentioned? These problems would involve the watchdog timer and the CRC.

    The work-around using daisy chain mode would be using using the MCU to scan for the bit pattern from Table 4 and Table 6 of the previous revision of the datasheet and then blocking that particular bit pattern. This was originally identified as a problem when there were multiple devices on the SPI bus, where the DACx760 or DACx750 may erroneously receive a command to enable either the CRC or watchdog timer. However, this may be a problem with daisy chain mode as well. 

    The device may be operating, but if the CRC is erroneously enabled, then you may lose communication with the device. Furthermore, if the CRC is enabled in this way, the CRC may not be disabled with the standard communication and a power cycle may be required.

    There isn't a straight replacement device to the DAC8760, but the DAC8775 may be a close substitute in function. It is a little more complex with four output channels, and a built-in dc-dc controller.

    Again, I want to be sure that is seeing a problem in the application, could you please give some more details about it?


    Joseph Wu