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Found this on fpga-faq. Hope this helps http://www.fpga-faq.com/archives/89125.html ------ Article: 89141 Subject: Re: Reprogramming one MAXII EPM1270 vs security bit set From: "Luis Cupido" <cupidoREMOVE@REMOVEua.pt> Date: Tue, 6 Sep 2005 17:26:25 +0100 Links: << >> << T >> << A >> Hi, Similar situation happened to a friend of mine. He found out that while inspecting signals with the scope or placing the finger over the Jtag lines the MAXII loaded fine. Altera did release a note about how sensitive some MAX II devices were regarding the electrical behavior of the JTAG signals... can't remember where it is but you will find it for sure at the altera site. Over here all worked fine, but I do have a very long JTAG cable (2m) with the original byteblasterMV it sometimes fail :( Looks like silicon versions respond differently... the ES (engineering samples) devices were more picky than the regular ones ! but that is not scientific knowledge, just my impression. Since on the long cable (that is more convenient here) it works always I just forgot about this issue and keep on developing the VHDL :) Luis C. <abeaujean@gillam-fei.be> wrote in message news:1125911324.912543.131210@o13g2000cwo.googlegroups.com... > Hi group, > > I would like to share an impression I have. > > Trying to erase and/or reprogram one Altera MAXII EPM1270 device using > the Quartus 5.0 Sp1 Web free edition software and the ByteBlasterII > programming adapter kept on failing (same thing with ByteBlasterMV and > previous revision of the soft). > > After considering lots of possibilities (missing pullups, pulldowns, > JTAG clock with glitches, although none observed), I finally decided to > have the component de-soldered and a new one resoldered. > > IT NOW WORKS. > > Re-thinking the whole thing from the start, I now wonder if this > behaviour is not due to the previous use of the security bit. I > remember I set the security bit once on that device (on two different > prototypes, both of which were exhibiting the same problem). > > The security bit, once set, should I believe not prevent the component > from being erased and re-programmed (am I right or wrong ?). If you > read the MAXII specification, it seems so. > > The symptoms were : > > Error: Can't recognize silicon ID for device 1 > Error: Operation failed > > on both prototypes. > > Both prototypes are now working with the new soldered components. > > Has anyone experienced such a behaviour before ? > > So, I do believe that the problem could be once the security bit is > set. > > It could also be due to an incorrect definition of the length of two > non Altera devices part of this JTAG chain (4 instead of 16), but > anyway it is so strange that one could set a condition in the component > that prevents it from being re-programmed. > > Software bug ? > > Any idea ? > -------
