Pulling DMA low

[Anthony Ortiz]

Sorry for what might be a stupid question but I’ve been pulling the DMA line low by setting my gpio pin to output and clearing it, which sends a digital zero to the Dma line and that seems to work. However, searching online I see mention of simulating an open collector output by setting the gpio to input instead. I would like to do this the right way, so I’m wondering what the correct method is, and whether connecting it to ground will suffice.

Thanks in advance!

[Michael J. Mahon]

If I understand correctly, to assert /DMA you switch the GPIO to “output”
and output “0”, and to de-assert it you switch the GPIO to “input”.

This is the functional equivalent of using an open collector gate, so
you’re fine!

--
-michael - NadaNet 3.1 and AppleCrate II: http://michaeljmahon.com

[Anthony Ortiz]

> If I understand correctly, to assert /DMA you switch the GPIO to “output”
> and output “0”, and to de-assert it you switch the GPIO to “input”.
>
> This is the functional equivalent of using an open collector gate, so
> you’re fine!
>
> --
> -michael - NadaNet 3.1 and AppleCrate II: http://michaeljmahon.com

Thanks Michael! You're the man!!