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Can I disable Brownout by simply tying to Vdd? — Parallax Forums

Can I disable Brownout by simply tying to Vdd?

PaulFPaulF Posts: 62
edited 2009-11-17 07:29 in Propeller 1
Apologies, I think that this has been asked before but I can't find it after searching a number of times.

I have (amongst many other components) two 5V reed relays (with diode protection) controlled via FET transistors (2n7000). The contacts associated with these relays are completely isolated from the rest of the circuit and go only to an external circuit.

This external circuit consists of a 24V dc supply feeding each of the contacts and at the moment an LED with current limiting resistor from each of the contacts.

My problem is the Propeller shuts down when I power up or down the power supply feeding the 24V external circuit. There is a separate power supply feeding the propeller circuit.

Two questions:

1) I have BOEn connected to Vss as per the proto board. Is this the most likely cause of my problem or should I look elsewhere?

2) Is it OK to simply tie BOEn to Vdd or should I connect via a pullup resistor?

Paul

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"There are 10 types of people in the world. Those who understand binary and those who don't."

Comments

  • Mike GreenMike Green Posts: 23,101
    edited 2009-11-10 21:56
    You're asking the wrong questions. Your question should be "How can a supposedly isolated circuit involving a 24VDC power supply, a couple of LEDs and their current limiting resistors, along with reed relay contacts cause a Propeller in the reed relay coil circuit to reset?"

    There is some kind of coupling going on between the two circuits. It could be inductive if the wiring for both circuits runs together for some distance or there could be some kind of connection or leakage between the two circuits. You need to find and fix that first.
  • DonEduardoDonEduardo Posts: 54
    edited 2009-11-15 19:11
    I kept having my propeller reset on a battery charger I'm building. It would go for a while, and then reset at what seemed to be random times. However I finally noticed that it would reset when almost anything powered by the same wall circuit was turned on or off. Just today I put a .1uf capacitor across the resn pin and ground. That seemed to have solved the problem. I've turned off and on everything around it and it hasn't reset all day. I have not noticed any negative consequences of doing this.
  • Bobb FwedBobb Fwed Posts: 1,119
    edited 2009-11-17 07:29
    DonEduardo said...
    I kept having my propeller reset on a battery charger I'm building. It would go for a while, and then reset at what seemed to be random times. However I finally noticed that it would reset when almost anything powered by the same wall circuit was turned on or off. Just today I put a .1uf capacitor across the resn pin and ground. That seemed to have solved the problem. I've turned off and on everything around it and it hasn't reset all day. I have not noticed any negative consequences of doing this.
    I have found the same solution to work on EMI-plagued project I worked on. A 2.2KOhm resistor to Vdd and 0.1µF cap on the RES pin did the trick.

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    April, 2008: when I discovered the answers to all my micro-computational-botherations!

    Some of my objects:
    MCP3X0X ADC Driver - Programmable Schmitt inputs, frequency reading, and more!
    Simple Propeller-based Database - Making life easier and more readable for all your EEPROM storage needs.
    String Manipulation Library - Don't allow strings to be the bane of the Propeller, bend them to your will!
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