Very strange behaviour of ATtiny13A

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#1
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Hi folks!

 

I have a PCB I made to host a tiny 13A

 

I have a bizarre situation, I think it is some initialisation problem, or fuses. Please help !!

 

When I upload my program (assembler in Studio) I get nice 6uA in sleep (8 seconds, woken up by Watchdog.

 

This is good, the board is powered from LiPo cell.

 

However, when I cycle power, the multimeter shows 230 uA

 

I have no idea what reason :( Reset is pulled up to Vcc with 4.7kOhm, no other resistive load, all ports are only woken up when needed. Comparator  is off, ADC is used only momentarily, every hour. 

 

There is one button with internal pull-up, connected to the GND, normally open, no current there.

 

Have you evere experienced such funny behaviour?

Greetings, Tom

Last Edited: Sun. Apr 19, 2015 - 05:23 PM
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Do we get to see the code? Or is this one of those fun guessing games? 

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Yeah, you are right.

 

Here you go: https://www.assembla.com/code/sq...

 

hf.asm is the main file

 

Greetings, Tom

Last Edited: Sun. Apr 19, 2015 - 05:47 PM
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Uh, sorry friends !!!!

 

I found the culprit. Probably the tiny was malfunctioning, I took a fresh one and it is 6uA all the way :)

 

Good lesson :)

Greetings, Tom

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Also, set up the brown-out-detector. If the power rises too slowly from a brown out situation, the processor might not start properly. The "BOD" will solve this.

The largest known prime number: 282589933-1

In my humble opinion, I'm always right. 

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Thanks, indeed I have. It is set for 2.8V, but I use BODCR to put it to sleep every time the processor sleep. After waking up, it is on automatically. Vcc was over 4V all time.
I think I killed it will zillions of DW fuse changes when I went rampant debugging the beast :)

Greetings, Tom

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Hi again!
I have recreated the error :)
I powered the board from LiPo cell, 3.7V - 4V read back by Atmel ICE.
Normally, all was ok - I could debug and go back to ISP programming
However, when I added a multimeter to measure the current, the power was insufficient for correct operation. I got 0x0c error.
When I powered directly, the situation was corrected and back to normal. The chip lives on :)
Good luck!

Greetings, Tom

Last Edited: Mon. Apr 20, 2015 - 01:23 PM
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when I added a multimeter to measure the current,

In SERIES of course.... How much voltage does your meter drop? Do you have another meter to measure this?

 

And of course you MUST have bypass caps or inserting the meter in series with VCC will cause havoc.

 

John Samperi

Ampertronics Pty. Ltd.

www.ampertronics.com.au

* Electronic Design * Custom Products * Contract Assembly

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Hmm, I simply put it in series battery -> meter -> Vcc
I will try to measure the drop, however I have no idea about bypass caps. Of course I have two at the battery connector and two on Vcc pin.
I will read more about power consumption measurements :)

Greetings, Tom

Last Edited: Mon. Apr 20, 2015 - 11:07 PM