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Altera_Forum's avatar
Altera_Forum
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14 years ago

Cyclone III stays in POR forever

I'm using EP3C5E144, and tried download code through JTAG and configuration port without success. I found the pins nSTATUS, nCONFIG and CONF_DONE are all logic low. Does this mean the chip is in Power On Reset? I have +1.2V supply for VCCINT and VCCD_PLL1,2; +2.5V for VCCA1,2, and +3.3V for all VCCIOs. MSEL2 and MSEL0 grounded. MSEL1 is connected to +2.5V. All these voltages are good. What could make the chip stays in POR?

4 Replies

  • Altera_Forum's avatar
    Altera_Forum
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    14 years ago

    hi

    if i i'm not mistaken ....

    nSTATUS, nCONFIG and CONF_DONE have to conect to vcc..... put 10k res...

    if you put this pins to gnd your system stay on por

    cheers

    Franz Wagner
  • Altera_Forum's avatar
    Altera_Forum
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    14 years ago

    restating franz, nCONFIG is an input and should not be low. it should be pulled up by 10K resistor or directly to VCCio. nSTATUS and nCONF_DONE are bidir and they should be pulled up by 10K resistor.

    nCONFIG low puts chip in configuration mode. if it is already pull'd up, then i would say you have a short to ground.
  • Altera_Forum's avatar
    Altera_Forum
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    14 years ago

    Thanks, you guys. These pins are pulled up with 10K resisters already.

    By reading another thread, I found out that the E-PAD under the chips was not soldered to GND very well (cold-joint). Now the problem has been fixed. Have a good day.:)