AVR MEGA8L problem

sarang1_in said:

Hi all.
I have used a MEGA8L to give pulses to ignition coil for generatring sparks. The pulses are generated by a timer 555, and I am only making a pin high or low. for 10 secs. Repeatedly for 3 times. I am igniting the oxi-acetelene flame which I am sensing and making the sparker off. When coil is not connected everything works fine( On and Off the timer pulse generator for 3 times) but as soon as I connect the coil the pin of MEGA8L goes high and coil starts sparking contienously and does not repeat the sequence for 3 times (It remains contineously On instead of On and Off)
The coil is placed 3 to 4 meters apart from the actual circuit. AVR operates on 5V and coil on 12V, but the ground of both is common. Is it EMI which is creating problem?? Please suggest something as I can't isolate the grounds (and sometimes that also doesn't work)

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techknow said:

can any one give me a circuit diagram of AT90S2313 programmer (serial/parallel) hope for soon

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sarang1_in said:

No. The output should be 1(HIGH) for six secs and 0(LOW) for 2 secs. This cycle is repeated for 3 times. But after connecting the Sparker coil it(The output) becomes contineous.

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