Forum Discussion

Altera_Forum's avatar
Altera_Forum
Icon for Honored Contributor rankHonored Contributor
14 years ago

EP4CE6F17I8LN no JTAG, nSTATUS stuck low

Hello All,

I have an interesting Cyclone IV problem. I'm using an I8LN by accident. I bought the wrong device; I'm using 1.2V for Vcore - when the 'L' part specifies 1.0V. My understanding is that it should still work... right? I just won't realise low power. Certainly JTAG should be happy...?

My symptoms:

- no jtag access according to programmer/jtag debugger

- activity on TCK, TMS, TDO, TDI, none are stuck, my blaster works fine

- TMS, TDI - 10K pull up to 2.5V

- TCK - 1K pull down to GND

- nCE - driven hard GND

- nSTATUS is 0V

- it has a pull up 10k to 2.5V

- with power removed, this pin has about 10Kohm to GND - so no placement problem

- nCONFIG is 2.5V and has a 10k pull up to 2.5V

- CONFIG_DONE is 2.5V and has a 10k pull up to 2.5V

- MSEL2,1,0 = 010 = AS standard POR delay.

- All power rails from linear supplies, 3.3V, 2.5V, 1.2V nice and clean.

As far as I can tell I'm doing every (except the core voltage by the book.) Is this enough to sink my boat? Any tips would be greatly appreciated.

1 Reply

  • Altera_Forum's avatar
    Altera_Forum
    Icon for Honored Contributor rankHonored Contributor

    I did the same thing... I have a "LN" low power version on a board with 1.2V VccINT and nStatus won't go high.

    Did you find out what the issue was? Can a "LN" part be used with 1.2V VccINT?