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Altera_Forum
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18 years ago

CIII / Configuration

Hi,

I have a cyclone EP3C10F256C8 and configuration flash EPCS4SI8N. I have 2 of 10 boards which won't configure. All the signals are present: DCLK coming from the FPGA, CS, ASDI, and DATA coming out of the flash.

In my reading I noticed that the flash drives out on the falling edge of DCLK and the FPGA latches also on the falling edge--is this correct? It seems more logical for the FPGA to latch on the rising edge if the flash is sending out on the falling edge. Otherwise it would seem that the tsu would be rather tight.

The data line is point to point and is approximately 17mm in length.

The clock line is point to point and is approximately 18mm in length.

I believe I'm running into a timing problem but I can't figure out why 8 boards work great while 2 are behaving erratically.

Any help would be greatly appreciated.

Best regards,

Rob

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  • Altera_Forum's avatar
    Altera_Forum
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    18 years ago

    What's your voltage for Vccio of IO bank 1 and setting for MSEL?

    Whats DCLK frequency?

  • Altera_Forum's avatar
    Altera_Forum
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    18 years ago

    Thank you.

    But yes, both parts are RoHS compliant. In fact, the whole board was done with RoHS compliance. But you bring up a good point about the RoHS process.

    Rob
  • Altera_Forum's avatar
    Altera_Forum
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    18 years ago

    --- Quote Start ---

    I have a cyclone EP3C10F256C8 and configuration flash EPCS4SI8N.

    --- Quote End ---

    Does the EP3C10F256C8 have an N postfix? i.e. is it a lead free part? The Flash you mention is a lead fre part

    Mixing Lead Free and Leaded parts needs careful control at assembly.

    I only say that because I have worked on a mixed board and seen signal integrity problems on some PCBs due to incorrect solder temperatures.

    From the Altera website:

    Q: Can I use both leaded and RoHS-compliant parts on the same board?

    A: Yes, both leaded and RoHS-compliant parts can be used on the same board. There are high-volume consumer products that are currently using both types of packages. However, using both lead and RoHS-compliant parts together will add to the complexity of the manufacturing process. Altera does not recommend this design for volume production.

    Might be worth checking with the PCB assembler.