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taligentx / dscKeybusInterface

An Arduino/esp8266/esp32 library to directly interface with DSC security systems.
GNU General Public License v3.0
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D8 is not a good pin for input on NodeMCU #268

Closed toddlipcon closed 2 years ago

toddlipcon commented 2 years ago

The NodeMCU fails to boot if D8 is pulled low. D7 seems like a bette choice according to https://randomnerdtutorials.com/esp8266-pinout-reference-gpios/

taligentx commented 2 years ago

Hi @toddlipcon - can you clarify what would cause D8 to be pulled low or high by the rest of the circuit? D8 is connected to the NPN base, it shouldn't be affected by voltage at the collector.

toddlipcon commented 2 years ago

In the README, it suggests that D8 is suitable as an input pin (connected via the voltage divider on the clock or data keybus lines). Those lines might be pulled low by the panel or other keypads transmitting on the bus, which would result in a low voltage on D8 during boot. If, at boot time, the NodeMCU sees D8 pulled low, it won't boot.

So, I think it's suitable as an output (connected to NPN base) but not as an input.

taligentx commented 2 years ago

Gotcha, the pin documentation was updated in develop back in 4d1d7fa4aa3dd7a13506c7010029a818bedb4c67 to only list single pins instead of listing a range of pins so it'll show up in master at the next release.