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Lose 1-wire when pwm to MOSFET is above 0  

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(@helibrewer)
Eminent Member
Joined: 4 years ago
Posts: 28
May 23, 2020 7:55 pm  

Wondering if I have too much current demand on my prototype.

MEGA board, wifi shield, 1-wire(port 12), MOSFET driving an LED (port 6)

I have a 12V/3A wall-wart plugged into the MEGA, all devices are supplied by native 5V.

Whenever the pwm value for the MOSFET is greater than 0, the 1-wire bus drops off and gives a value of -196, as if the pull-up resistor has been removed. If I change the pmw value back to 0, the 1-wire comes back online.

The MOSFET Vin is 5Vcc

 


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(@pbruno3)
Reputable Member Admin
Joined: 4 years ago
Posts: 287
May 23, 2020 8:29 pm  

Maybe not wired correctly? What type of power supply is it? Wall warts are notoriously terrible. I'd recommend something more industrial quality. Switching supply.


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(@helibrewer)
Eminent Member
Joined: 4 years ago
Posts: 28
May 23, 2020 8:42 pm  

It's a temp setup for testing/learning....I have good power supplies for my enclosure once I get my design down


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(@pbruno3)
Reputable Member Admin
Joined: 4 years ago
Posts: 287
May 24, 2020 5:10 pm  

Do you have a schematic you can share?


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(@helibrewer)
Eminent Member
Joined: 4 years ago
Posts: 28
May 24, 2020 8:03 pm  

@pbruno3 I resolved it but I'm not sure why it worked. I switched the MOSFET ground from the breadboard rail to a ground pin on the shield.


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