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Altera_Forum
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17 years ago

Can not dowload the code into my Altera

I met a weird problem: I can download the code into my Altera chip EPM240T100 comfortably at the first time. But, I can not download the code again. The errors are: Error: Can't access JTAG cha...
Altera_Forum's avatar
Altera_Forum
Icon for Honored Contributor rankHonored Contributor
17 years ago

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Thanks for your reply.

I found the problem.For some reasons, the TMS, TDI, TDO and TCk pins were accidentally connected to four unused I/O pins besides being connected to the JTAG head. I cut the connections to the 4 I/O pins, it works.

Also, I noticed that in Settings, there is "Unused Pins" tab. I changed the setting of "Reserve all unused pins" from "As Output driving ground" to "As input tri-stated with weak pull-up resistor" and it works! I can download the code without cutting the connections mentioned above.

However, I found one of my output pin which was supposed to drve a LED does not work after changing the setting. Such pin is an output pin and it is not an "unused pin". I do not know why my setting change can affect it....

any idea?

Thank you!

--- Quote End ---

Hi,

great to hear that your main problem is solved. Regarding your Pin problem, you should check your Pin Assignment together with the schematics of your board. Maybe the LED is connected to one of your connection which you have cut ?

Kind regards

GPK