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Valued Contributor III
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Problem with JTAG

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 ?
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3 Replies
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Valued Contributor III

Re: Problem with JTAG

"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.
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Valued Contributor III

Re: Problem with JTAG

 

--- 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:).
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Valued Contributor III

Re: Problem with JTAG

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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