Problem with JTAG

Question

Hi everybody

I've a problem with my MAXII I can't tranfert my program with quartus.

When my CPLD is under 3V I measure an impedance of 10K on TDI and more than 1M for other between ground and th pins.

Now when I plug the USB blaster and an oscilloscope on JTAG pins I have the following result when I press start in the programmer:

TDO: 1.5V peak

TCK: 3V peak

TDI: 3V peak

TMS: nothing

I thougth my CPLD was dead but when I turn off the CPLD there is no more signal on JTAG pins.

Someone have an idea ?

altera_forum · Answer

"TMS: nothing" means, the pin is either shorted or the programmer connection broken. You have to fix this first.

P.S.:

--- Quote Start ---

When my CPLD is under 3V I measure an impedance of 10K on TDI and more than 1M for other between ground and th pins.

--- Quote End ---

Seems like the design lacks the suggested TCK pulldown resistor.

altera_forum · Answer

--- Quote Start ---

"TMS: nothing" means, the pin is either shorted or the programmer connection broken. You have to fix this first.

--- Quote End ---

I try again to find what's going on this pin.

--- Quote Start ---

P.S.:

Seems like the design lacks the suggested TCK pulldown resistor.

--- Quote End ---

I've read that altera device had intern weak pull up/down resistor and that was useless to add external resistor. But I'll try it too.

Thanks for your help. I'll post when I've fix it (or not :cry:).

altera_forum · Answer

I've add the pull up and the pull down resistor and when I press start on the programmer

TDO: 1.5 V peak 0 before

TCK: 3V peak 0 before

TDI: 0.6V before then 0V then 3v when I click

TMS: 0V before at 3V

But my device is not recognised, I can't program it.

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