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Electronics => Electronics => Topic started by: roi_tau on December 16, 2008, 01:07:10 PM

Title: my uC doesnt work with 3.6 volt battery
Post by: roi_tau on December 16, 2008, 01:07:10 PM
Hi guys


In one circuit I'm using PIC16F886. In the datasheet they say operation voltage is 2-5.5 volt,

However,If I connect the board to a 3.6 volt supply (I'm using power supply),nothing work

Only after I increase the voltage to 4 or 4.3 volt,the circuit works fine.

Does anyone knows what can be the problem ? I tried it with the PIC16F84A and it worked fine with 3.6 volt


Thank in advance

Roi
Title: Re: my uC doesnt work with 3.6 volt battery
Post by: izua on December 16, 2008, 03:41:15 PM
lower voltage = lower speed. check your clock/crystal.
Title: Re: my uC doesnt work with 3.6 volt battery
Post by: HDL_CinC_Dragon on December 16, 2008, 09:01:52 PM
Are you running anything else in the circuit other than the uC at the same time?
Title: Re: my uC doesnt work with 3.6 volt battery
Post by: roi_tau on December 17, 2008, 02:21:11 AM
First of all thank you for the reply,


Im not running anything beside the uC.


The crystal may be the problem. Im using internal osiclator that I defined to be 4Mhz

Maybe I reduce it to 1Mhz or 32Khz,

What do you say?


Roi
Title: Re: my uC doesnt work with 3.6 volt battery
Post by: izua on December 17, 2008, 06:35:51 AM
Quote
I tried to change the clock but it changes the time in the circuit.

8Mhz=> 1Mhz  ==>>  delay (8 sec) => delay(1 sec)

The uC must work with 3.6V and without external osc.

Can you help me?

Please do not send me pm, unless you have to discuss personal matters.
The mcu only know to delay in oscillations. So 1 sec is converted into a number of oscillations to be wasted.
If you lower the clock, the same number of oscillations occurs in a longer time range.

You need to recompile your code with the new cpu speed.