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Altera_Forum
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10 years ago

JTAG Tolerence for MAX5 Device 5M2210Z

I am using Max5 5M2210Z device in one of my projects.

In this I am configuring Bank1 voltage level as 1.8V. Since JTAG is also going to the bank1, the JTAG level should be 1.8V too.

I want to give the option for programming JTAG from the JTAG header for CPLD or from BMC.

Here is my doubt, the JTAG level for BMC is 3.3V and for the CPLD it is 1.8V.

Will the pins be able to handle 3.3V level signals without using and voltage translators?

Hoping for a quick response.

2 Replies

  • Altera_Forum's avatar
    Altera_Forum
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    10 years ago

    Look at the dc and switching characteristics for max v devices' 'dc and switching characteristics for max v devices (https://www.altera.com/content/dam/altera-www/global/en_us/pdfs/literature/hb/max-v/mv51003.pdf) for Max V. Yes the pins will tolerate 3.3V. However, if you're operating a bank at 1.8V the recommended max level is 1.89V. Persistent over-driving of a pin could result in damage - eventually.

    However, what is your BMC (?) going to make of the 1.8V TDO signal driven towards it? It's expecting a 3.3V logic levels, probably with a minimum V_high threshold of 2.2 to 2.5V. What's it going to make of a 1.8V logic high?

    My suggestion - use level translators.

    Cheers,

    Alex
  • Altera_Forum's avatar
    Altera_Forum
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    10 years ago

    Yeah..seems like that be a better option to use level translators.

    Thnx alex