Searching IO0 Pin

mattismyo
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Joined: Sat Jun 10, 2017 6:56 am

Searching IO0 Pin

Postby mattismyo » Tue Jul 18, 2017 6:30 pm

Can somebody tell me please, where the IO0 Pin should be?
Image

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kolban
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Re: Searching IO0 Pin

Postby kolban » Tue Jul 18, 2017 7:05 pm

Do you have a link to the source of the board? Maybe the manufacturers page?
Free book on ESP32 available here: https://leanpub.com/kolban-ESP32

mattismyo
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Joined: Sat Jun 10, 2017 6:56 am

Re: Searching IO0 Pin

Postby mattismyo » Tue Jul 18, 2017 7:10 pm

Sorry, but i bought this one from ebay. On the backside of the esp32 is written:

ESP32 DEVKIT V1
http://www.doit.am

I found this here:
https://github.com/SmartArduino/SZDOITW ... 66---ESP32
https://github.com/SmartArduino/ESP/blo ... rESP32.pdf

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loboris
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Re: Searching IO0 Pin

Postby loboris » Tue Jul 18, 2017 7:24 pm

BOOT button is usually connected to GPIO0 and EN switch to CHIP_PU/Chip Enable/EN

mattismyo
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Re: Searching IO0 Pin

Postby mattismyo » Tue Jul 18, 2017 8:10 pm

Yes, i can see this here

Image

But still can't find out, where IO0 should be. Also tried to follow the wiring, but without success.

WiFive
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Re: Searching IO0 Pin

Postby WiFive » Tue Jul 18, 2017 9:04 pm

There is no header pin for GPIO 0 and 6-11 (flash pins)

mattismyo
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Joined: Sat Jun 10, 2017 6:56 am

Re: Searching IO0 Pin

Postby mattismyo » Tue Jul 18, 2017 9:08 pm

I want to enter download mode with GPIO 2 by connecting it to GPIO 0. So this is not possible? Or is there another way to do so?

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kolban
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Re: Searching IO0 Pin

Postby kolban » Tue Jul 18, 2017 10:49 pm

There may not be a header pin for GPIO 0 on that board, but there are on others including Espressif's module. See:

https://dl.espressif.com/dl/schematics/ ... ard-v2.jpg

6th pin from the top right.
Free book on ESP32 available here: https://leanpub.com/kolban-ESP32

samsam
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Re: Searching IO0 Pin

Postby samsam » Wed Jul 19, 2017 5:04 am

If the schematic of your module is the same as the one you've posted, then you can solder one jumper wire on the pad of the BOOT button @ the pad that is connected to pad 25 - IO0 of the ESP-WROOM-32 module (which is on the picture you posted first - on the right side the bottom one). The other pad of the BOOT button goes to the GND..

Take in mind that the schematic that you've posted maybe is not exact what your board is - on mine board there is 470 ohm resistor between the BOOT button and the IO0 - so check first with multimeter, then if there is some extra resistor in between deside if it still works for your case or not, but the pad of the button is the easiest place you could still solder without serious risk to damage the board ;)

samsam
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Re: Searching IO0 Pin

Postby samsam » Wed Jul 19, 2017 5:48 pm

mattismyo wrote:I want to enter download mode with GPIO 2 by connecting it to GPIO 0. So this is not possible? Or is there another way to do so?
Can you elaborate a little more what and how you trying, because I guess you could be on the wrong track:
In order to be in boot download mode both IO0 and IO2 should be low (i.e. grounded). IO2 is already low, because there is 10k pull down resistor, but IO0 is high because is pulled up also with 10k. Just connecting both together will give you 1.65V or half of the supplied voltage if is different than 3.3V, so you'll stuck in the middle of nowhere: as per the specs 5.1Absolute Maximum Ratings: to be consider IO signal high it need to be Vih>0.75Vio and to be low Vil<0.25Vio ... :( I doubt (if this was your intent) anybody here could bet in what mode the mcu will boot :(

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