Comment on Digital buffer works for a bit, then stops, turning it off for an hour resets it to working again

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litchralee@sh.itjust.works ⁨2⁩ ⁨weeks⁩ ago

(sorry for the long delay)

From your description, I’m wondering if the internal pull-up from the bike computer might actually be an active output, and that the open-drain buffer is causing the bike computer to give up sourcing that pull-up voltage. That is to say, if a larger-than-expected current is drawn from the bike computer, it might trigger a protection mechanism to avoid damage to its output circuitry.

To that end, I would imagine that either: 1) an inline resistor to limit drain current, 2) a push-pull buffer, or 3) both, would help rectify the issue.

My suspicion is based purely on the fact that getting stuck low for an open-drain device could be an issue “upstream”. If it were stuck high, I wouldn’t normally suspect this path.

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