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DAC8734: How to treat the GPIO when not used?

AnBer
Mastermind 30160 points
Part Number: DAC8734

Team,

-Could you please clarify the function of the GPIO. What is the typical use case?

-Is it better to provision the design to enable the use of the GPIO "in case of"? For example can it be used for debug purpose?

-When GPIO will not be used at all: I assume that it can safely be left unconnected (since the default status is high impedance - as described in Tab 4 page 26 of  SBAS465A). Correct?

Thanks in advance,

Anthony

  • 0
    TI__Mastermind 46290 points
    Hello Anthony,

    It's a bit hard to firmly comment on what the Product Definer was thinking for this product, but generally the intention I've seen for such things is quite simply for providing additional GPIOs. There can be various motivations for it - be it limited pin-resources on the MCU and this allowing you to get some GPIOs out of the pins you've assigned for the SPI via the DAC or potentially for applications where isolation is included - this allows you to have two GPIO pins on the hot-side of the isolation barrier without having to run additional lines across the barrier - so again you're getting GPIOs via SPI.

    Using it for a debug routine is an interesting proposal. Generally I see people instead performing this with more simplistic read-back routines to either ensure device power-up or in initial development to ensure that write / read cycles are behaving correctly. However, it certainly could be used for a debug / health-check routine (maybe for safety applications toggling the GPIOs and looping them back to the MCU to validate that the digital core is still alive and performing as expected).

    As you said by default the pins are high-impedance nodes and configured as inputs, so leaving it floating would be fine.