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Re: The Rx pin doesn't go down to 0V

PostPosted: Thu Jan 06, 2022 4:44 pm
by jmattioni
OK, I've resolved my issue. The basic problem is that the level converter I'm using isn't designed to drive an input with a pull-up. The ESP8266 RX pin has a built-in pull-up holding it at 3.3v. I got around this by using a PNP switching transistor.

Re: The Rx pin doesn't go down to 0V

PostPosted: Tue Jan 11, 2022 12:29 am
by UN26uxx
jmattioni wrote:OK, I've resolved my issue. The basic problem is that the level converter I'm using isn't designed to drive an input with a pull-up.

Good news, there is a way to deal with this.

jmattioni wrote:The ESP8266 RX pin has a built-in pull-up holding it at 3.3v. I got around this by using a PNP switching transistor.

Can you explain me more in details this ? Through a schematic if possible to be as clear as possible for everybody.
I'm not an expert with electronics. I already saw some pull-up or pull-down using a NPN transistor. But I'm not sure if it's the same or not. Honestly I tried to do some, but it wasn't working, it's possible I haven't plug it correctly.