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RON1406
Joined: 17 Feb 2005 Posts: 15 Location: Opwijk
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Posted: Tue May 21, 2013 9:53 pm Post subject: Problem with USB-ISP programmer and Mega644 |
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Hello,
I can't program a mega644 with the USB-ISP programmer I bought from MCS , some years ago. When I connect the programmer to a Mega8515 board , it works perfect. After this , I programmed the Mega644 with a Leaper48 programmer , I loaded it with a small led program , so I could see the Mega644 was working. The Leaper48 programmed the Mega644 perfectly. I verified the board connections over and over , they look fine as Mega8515 and Mega644 have the same program-pins at the same place. So .... am I doing something wrong or so? With a logic probe , I see some pulses to mosi , miso and the reset. It looks like there is a very short time of communication. When I want to go to the "Program chip F4" , it says it can't read the ID of the chip. The Bascom version I use is 2.0.7.6 and the computer has XP SP3 operating system. Can someone help me here?
Many thanks,
Ron, |
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albertsm
Joined: 09 Apr 2004 Posts: 5913 Location: Holland
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Posted: Tue May 21, 2013 10:14 pm Post subject: |
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there is a speed setting in the programmer options. try a low speed (1)
And do not install the jumper : without the jumper it is powered from the circuit which is best. _________________ Mark |
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RON1406
Joined: 17 Feb 2005 Posts: 15 Location: Opwijk
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Posted: Wed May 22, 2013 5:49 am Post subject: |
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I tried all the speeds ... from 0 to 10 and it didn't change something. I also tried a second Mega644 ... still the same. Really strange ... and the programmer connected to a Mega8515 board , it works fantastic. Is there something wrong with the ID-code of the chips? As I think that when the code isn't right , the programmer even doesn't want to erase the chip and so. When the Mega644 was running with the little led-blinking program , I even can't sent a "reset the chip" , the Mega644 keeps on running ..... |
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albertsm
Joined: 09 Apr 2004 Posts: 5913 Location: Holland
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Posted: Wed May 22, 2013 9:00 am Post subject: |
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early models did not have an option to change the speed. the manufacturer add it later. but it is there since some years.
if the ID can not be read, the programmer will not program the chip. you can try with the other programmer to read the ID.
sometimes the ID gets damaged but in most cases a wrong fuse byte setting will result in problems (selecting external clock for example).
If you have a new chip it should work since i tested on m644 in the past.
make sure that the reset pin is not connected to a capacitor. it can cause problems. _________________ Mark |
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RON1406
Joined: 17 Feb 2005 Posts: 15 Location: Opwijk
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Posted: Thu May 23, 2013 10:36 am Post subject: |
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Finally found it .... yep .... my mistake. I use 1 ohm resistors as bridges on the circuit board and one was used for the reset of the programmer to the Mega644. But I placed a resistor of 1k .... stupid huh!!! This resistor in series with the pull up of 1K makes it in fact a voltage divider by two and so the chip never saw the logic zero to be programmed then. Strange enough , my logic probe DID see the logic zero so I didn't pay attention to it.
Secondly , as the programming worked fine but now and then , when programming the fuse bits , there still happed something wrong what sometimes made the chip unusable. So I had to clear it again with the Leaper48. What I changed now is the pull up resistor of 1K for the reset circuit , I placed now a 10K resistor and for the moment , it works perfect , even when I'm "playing" with the fuse-bits. Mark , thanks for your patience and help .... I hope this won't happen again.
Greetings to you all !! |
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