Author Topic: strange pwm problem  (Read 1895 times)

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Offline superchikuTopic starter

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strange pwm problem
« on: March 12, 2008, 07:03:35 AM »
i hope my bot would start working it has got a strange probelm in pwm ,

when it is tested with only the mcu in the breadboard , i get exactly same values of pwm but when used in the bot one is lower than the other i dont know why this is happening can u help

and yes  both of my adc configurations are same so their corresponding pwm must be same so wat is the problem

mcu:atmega16
pwm channel used:oc0 and oc2
same prescaler and values

ADC:reference is AVCC and i have connected capacitor between aref and GND???



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Offline HDL_CinC_Dragon

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Re: strange pwm problem
« Reply #1 on: March 12, 2008, 02:25:17 PM »
electrolytic or mylar capacitor?
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Offline superchikuTopic starter

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Re: strange pwm problem
« Reply #2 on: March 12, 2008, 02:36:32 PM »
mica capacitor electrolytic would just blow up
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Offline superchikuTopic starter

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Re: strange pwm problem
« Reply #3 on: March 12, 2008, 02:38:35 PM »
it works on the breadboard but on the main crcuit board it just gets mad doing strange things with pwm

and yes i have triple checked the connections
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Offline ed1380

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Re: strange pwm problem
« Reply #4 on: March 12, 2008, 02:53:31 PM »
what is this main circuit board you're talking about? is it through hole, custom made pcb? etc.
Problems making the $50 robot circuit board?
click here. http://www.societyofrobots.com/robotforum/index.php?topic=3292.msg25198#msg25198

Offline superchikuTopic starter

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Re: strange pwm problem
« Reply #5 on: March 14, 2008, 06:49:17 AM »
main circuit board means the veroboard which is going to be attached to the bots
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Offline Admin

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Re: strange pwm problem
« Reply #6 on: March 15, 2008, 07:00:59 PM »
Quote
and yes  both of my adc configurations are same so their corresponding pwm must be same so wat is the problem
Is your ADC somehow controlling the PWM?

Quote
mica capacitor electrolytic would just blow up
your cap isn't rated at the right voltage

Quote
ADC:reference is AVCC and i have connected capacitor between aref and GND???
yeap, you need a cap there too

Offline superchikuTopic starter

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Re: strange pwm problem
« Reply #7 on: March 16, 2008, 01:06:15 AM »
thanks for the reply i found out the problem since iam using 2 different timers ,they are acting differently when connected to the veroboard i have adjusted the code accordingly and soon will be posting my bot's video
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