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problem in programming atmega 16L

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Moderators: Ajay, Junied , abbas1707, Arun Kumar V, pdi33, Shailesh NAYAK, ۞ TPS ۞, shyam, sashijoseph

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rahuljin

Mon Jun 30 2008, 09:19AM

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used and tested ??? how ??

i made the programmer without buffer chip. is it ok ??

pdi33

Mon Jun 30 2008, 11:37AM

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hi rahul,
the programmer without the buffer is o.k. but not safe as far as long term is concerned.
As far as the AVRstudio programmer is concerned, the hardware seems to be the same for the AVRISP programmer. Just go to Tools ->Program AVR -> connect and select 'STK500 or AVRISP' , the com port u have connected ur programmer and press 'connect'.

P.S. i personally use the ponyprog and have not tried the AVRstudio to program it.(as yet)

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rahuljin

Mon Jun 30 2008, 12:07PM

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thanks. one last think i want to ask. i get this circuit for test board, but it is active low. what is mean by active low and how i can make it active high. when i try to run a simple led program, opposite things happen. i programmer for 1 led to get on but other seven get ON and that one turns off.

pdi33

Mon Jun 30 2008, 12:23PM

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. I did not understand what u men when u said that the circuit was active low.maybe u meant the reset was active low. this means that the reset is asserted when a low signal (0v) is given to that pin.Similarly, the reset of 89xx uC is active high. hope u got the idea.

well,about the LED problem, i think u have connected the anode of LED to Vcc and the cathode to the port pin, right?.just connect the anode to the port pin and the cathode to ground and u will get the right output.

[ Edited Mon Jun 30 2008, 12:26PM ]

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rahuljin

Mon Jun 30 2008, 07:28PM

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thanks. i get it now. the pins r in opposite direction so opposite output. i will correct it. so thats it for now and for this thread.

rahuljin

Sat Jul 05 2008, 07:16AM

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i have a new problem. i added the resistor and capacitor(for reset) in the programmer so that i can test my codes in programmer without removing microcontroller, now it is not working. what if i dont use the capacitor ?
and how to use external oscillator ? i hav a 8 mhz crystal oscillator.

pdi33

Sat Jul 05 2008, 09:08AM

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hi rahul,
check ur reset pin if if is being pulled low by the programmer hardware. better remove the programmer connection from the reset pin and check the circuit. the circuit shown by u in the previous post seems to be perfectly alright except just try reducing the reset resistor value to say 10k instead of 100k aand capacitor to 10u instead of 0.1u..
as for ur second doubt, u can change the oscillator mode by changing the cksel fuses of the microcontroller. If u r using ponyprog, first read the fuses, then modify them acordingly and then write the modified value.
here is the screen shot of the fuse bit programming box of ponyprog:(click the button circled to bring up this box.

[ Edited Sat Jul 05 2008, 09:18AM ]

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pdi33

Sat Jul 05 2008, 09:16AM

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here is the fuse selection table for external crystal connection for various frequencies:

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rahuljin

Sat Jul 05 2008, 10:29AM

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ground and reset r shorted. is it correct ??

can i just put the oscillator in programmer but use the internal oscillator ?

[ Edited Sat Jul 05 2008, 10:38AM ]

pdi33

Sat Jul 05 2008, 10:44AM

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reset is not shorted to gnd. it is connected to gnd via a reset capacitor.

o.k......... yes, that is the mistake in ur previous circuit.remove the short between the reset and gnd. that would certainly reset the uC continuosly.

and yes, u can physically connect the crystal to the uC but still use the internal oscillator.

[ Edited Sat Jul 05 2008, 10:47AM ]

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