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- Hacker News
- Slopby aappleby
- I don't think it's slop -- the sources are books and it doesn't read like slop -- but the sources are more worth reading. It's more like an undergrad trying to fill word count, without getting why this is interesting.by blagie
- It's worth point out that on many microcontrollers (STM32's at least), configuring a pin as a "digital input" means that the signal is routed through a Schmitt trigger circuit that's built into the MCU.
This also means you'll want to ensure that any floating MCU pins are _not_ configured as digital inputs, as the Schmitt trigger circuit itself will waste power switching back and forth between high and low states constantly.
by wrigby - This makes no sense to me. The entire point of Schmitt triggers is to not switch back and forth constantly without a good reason. Something is missing from your explanation.
- > you'll want to ensure that any floating MCU pins
Stop right there. Floating CMOS inputs are generally not a good idea, even if they can be configured to shut off the digital receiver.
Yes, in some cases, you really can shut off the power to the digital receiver, but in the general case, you're better off configuring a pullup or pulldown on the pin, to keep it out of the CMOS transition region.
by zephen