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What are the pullups and pulldowns?

PostPosted: Thu Nov 10, 2016 8:25 am
by TarekJ
HI

- What are the pullups and pulldowns? are they important?
- What are their pins & values for esp8266-12f?
- I have a project using esp8266-12f with 8 relays, it is not stable, it disconnects the wifi repeatedly. it works fine without load, I have to assign more than 2k resistor for the LEDs to make it stable!!

any suggestions?

Re: What are the pullups and pulldowns?

PostPosted: Thu Nov 10, 2016 8:55 am
by Solomon Candy
I suggest you check the interwebs, there is sufficient information on pull-ups and pull-downs.
For the ESP pins you can checkout the technical reference manuals and other documentation on espressif.com, while keeping in mind what pins you have exposed on your ESP-12f (not ESP8266-12f, by the way).
Using the ESP8266 modules like 12f requires that you use a capacitor across input pins to cancel out ripples on varying load. See what value works for you, my guess would be around 50 uF should do. You can google for more accurate value as I haven't tried my-selves.

Re: What are the pullups and pulldowns?

PostPosted: Thu Nov 10, 2016 2:25 pm
by AcmeUK
What are the pullups and pulldowns? are they important?

See here :- http://playground.arduino.cc/CommonTopics/PullUpDownResistor

Re: What are the pullups and pulldowns?

PostPosted: Fri Nov 11, 2016 3:39 am
by TarekJ
Solomon Candy wrote:I suggest you check the interwebs, there is sufficient information on pull-ups and pull-downs.
For the ESP pins you can checkout the technical reference manuals and other documentation on espressif.com, while keeping in mind what pins you have exposed on your ESP-12f (not ESP8266-12f, by the way).
Using the ESP8266 modules like 12f requires that you use a capacitor across input pins to cancel out ripples on varying load. See what value works for you, my guess would be around 50 uF should do. You can google for more accurate value as I haven't tried my-selves.


Thank you, but I did not get "Using the ESP8266 modules like 12f requires that you use a capacitor across input pins to cancel out ripples on varying load." do you have a schema for that? where should I connect a capacitor ? does this make it unstable?