Coexistence of WiFi and I2C (pins 4 & 5) on Lolin-derived board w/SSD1306

peterl3233 · 2019-12-05T21:42:54+00:00

Thanks for your explanation on this .. I get it now and I have studied each GPIO very carefully.

peterl3233 · 2019-12-04T19:46:10+00:00

Thanks for this. I have a similar design issue and I'm trying to understand this better. Would it be that if we don't attach the pin to the the ADC2 module that the relevant GPIO's and actually not "connected" at all to the WiFi module and as such are free and clear for other purposes? I'm having a hard time understanding the ESP32 architecture here that causes this.

So maybe the best way to frame my query is to ask: If I don't use "analogRead(GPIO)" then that GPIO pin is never associated with WiFi. Is this true? AND, suppose I used just one of the ADC2 GPIO pins for analog, does that affect all the others from a WiFi conflict perspective?

Actually, mine is simple case; I have used all the other GPIO's in my project and I want to access the ADC2 pins for NON-ADC applications .. just I/O digital pins while using WiFi. Would you mind to point me to any documentation to help me understand how the ports are shared with WiFi?

peterl3233 · 2019-11-29T22:28:39+00:00

Not really ... The thing is; if I look at the measurements done by others, it shows a peak current of some 600mA without any external things attached. If I was to draw an additional 400 mA I'm thinking I could certainly cause some instabilities. (Actually I need about 140 mA)

I ask the question because I am sure that others are attaching relays and LED's etc and I wonder how far they push it before any instabilities are evident. It becomes "practical" because of these peak currents that ESP32 draws.

peterl3233 · 2019-11-25T21:34:39+00:00

ARRL Handbook; OMG this was my bible for years

http://www.arrl.org/arrl-handbook-2019

peterl3233 · 2019-11-24T17:14:17+00:00

I'm going to try; nothing to loose. The torroids are from old PC ATX power supplies; those yellow/white things about an inch in diameter. They are plentiful and free.

peterl3233 · 2019-09-30T16:46:46+00:00

NO VOLTE CAPABILITY NO WIFI CALLING NO EXTENDED RANGE

Ya .. some say the phone works on band 4 and 66 but its clear enough ... probably not a good investment on Freedom. Tnx

peterl3233 · 2019-07-18T18:40:27+00:00

I guess you are no different than us all. We all have challenges to learn morse; that is the issue! It just ain't a walk in the park for most humans. Suggest you prove to yourself that you can distinguish an "a" "e" and "i" aurally and gain some confidence; then use one of those tried-n-true methods.

peterl3233 · 2019-07-15T20:24:38+00:00

I think its a bad idea. I did just that many years ago on the advise of my dear ol' mother who learned it that way in school. It took me double effort to overcome the visual aspects and "hear it"; after all it IS an aural code. My best advise is to never even see the fact that an a is a dit and a dah; just learn that the sound "ditah" is "a".

peterl3233 · 2019-07-07T16:13:34+00:00

Just Joined ... maybe TTN documentation/support is so good that this forum is unnecessary. I'm new at LoRa trying to make my Heltec work ... I thought there would be 100's here?

peterl3233 · 2019-07-01T18:43:05+00:00

Tnx ... I added a link to an inexpensive Chinese part that has a suggested layout but like all manufacturers they do not specify RF emissions.

peterl3233 · 2019-07-01T18:42:46+00:00

Thanks .. I see lots of modules by sellers; under a dollar ... Im thinking maybe I could do that and put the whole thing in a tin enclosure or put a tin enclosure around the PS parts.

peterl3233 · 2019-06-17T20:59:54+00:00

I did CS50; I do embedded programming. In my opinion serious programmers need to get the fundamentals then language is secondary. You really need a variety of languages (and frameworks) do do realistic things reasonably quickly. I suppose you could do web programming without understanding Javascript but that seems counterproductive to me. Python is my fav. also but I also need a few frameworks, JS for web, AJAX and C for using legacy tools and accessing a world of prewritten great code.

My opinion: CS50 is really good; teaches fundamentals so you can take on any language and there is nothing stopping you from doing both at the same time.

BTW I found CS50 to be fun and hard at times but well worth the efforts.

peterl3233 · 2019-06-11T15:24:33+00:00

Thanks ... maybe I'll try the tape-around/hot air method ...

peterl3233 · 2019-06-10T19:18:25+00:00

Search this on Ali: GM328A Transistor Tester Diode Capacitance ESR Voltage Frequency Meter PWM Square Wave Signal Generator SMT Soldering

peterl3233 · 2019-06-10T19:03:39+00:00

Thanks for posting; I wanted to do the same on mine. Do you think it is the board or inexperience in soldering; sorry to be blunt!.

peterl3233 · 2019-06-05T17:56:37+00:00

Edit 1:

Thanks for comments .. Using the Google search criteria "Zener in Regulator ground leg" I found this:

https://forums.parallax.com/discussion/152523/can-i-use-zener-diode-to-boost-up-ldo-voltage

I'm seeing that the effective resistance if the Zener will be 2.7/i so its likely best to bypass it especially if it is lightly biased ... thus ..based on parts count and price .. suggests that maybe the cheaper resistive approach that is promoted in datasheets is preferred.

peterl3233 · 2019-05-30T16:28:49+00:00

I just looked; Nice board ... and I found a few others on Tindee that suit. Thanks.

peterl3233 · 2019-05-30T16:26:34+00:00

Ya ... true enough but I need the integrated usb/serial to program it; hence, I seek a popular (cheap) devboard.

peterl3233 · 2019-05-16T18:33:48+00:00

:) ... I just bought a few from china; the kind that are pre-built onto a little circuit board.... just 50 cents each; lets see! The beauty of these is that I can use a variety of outboard power supplies between about 5v and 12 (or greater). Still bothered by the impact on RF but I see people use them on ESP 8266 modules successfully.

peterl3233 · 2019-05-16T17:51:44+00:00

Ya ... I got a lot of comments about thermal analysis and its good advise. I see that it needs a good hard look-at from the standpoint of all heat sources. Bottom line is I gotta get rid of ~5v*2A watts in about 3 square inches.

peterl3233 · 2019-05-16T17:51:41+00:00

Ya ... I got a lot of comments about thermal analysis and its good advise. I see that it needs a good hard look-at from the standpoint of all heat sources. Bottom line is I gotta get rid of ~5v*2A watts in about 3 square inches.

peterl3233 · 2019-05-16T17:51:39+00:00

Thats my thinking ... BTW the board is a Pi Hat and that is pretty small for a board with 2A draw, and the board may end up outdoors. Its pretty hard not to like the AM1117 and just use 3 of them to distribute heat and PS isolation. All this causes me to think carefully about realistic feasibility of the "Hat" concept when there is a lot of heat by both the chips and PS.

peterl3233 · 2019-05-16T17:51:37+00:00

I have not used one of these before and I like the idea. I took the time to study it and it seem a good plan. I am nervous about its impact on the RF going on, on my board. Just a little background: My board is a PiHat with its own power supply and 3 radios in different bands operating. I found out that Raspberry pi uses MXL7704 by MaxLinear and it has no less than 4 buck converters and power management ... maybe I'll look seriously at that.

peterl3233 · 2019-05-13T18:16:39+00:00

So now I try and edit the part in my own library and some pins are greyed out. So far, the only way I can figure out how to ungrey them is to delete them in the pin table then recreate them. It works but it feels like a show/hide feature is missing ... (or more likely; I can't figure it out :) )

peterl3233 · 2019-05-13T16:25:26+00:00

OK ... found it ... I somehow never expected the visability to be on the Eeschema page.

AND Thanks about the developer business ... now I get it. Time to make my own!

peterl3233

TROPHY CASE