Can we have common JTAG programmer for different devices(FPG

[pkatiyar]

After reading too many articles on JTAG and understanding what JTAG really does, now I have a question. Please help me in resolving this:

1. Can we have commom JTAG programmer for uC, uP, FPGA, DSP. All this device may be from same manufacturer or different.

 

[mrflibble]

Re: Can we have common JTAG programmer for different devices

Does this link answer your question?

 

[pkatiyar]

Re: Can we have common JTAG programmer for different devices

Thanks for you reply.

What I have understood is that JTAG connector can be of different types but they all have common singals. So if a designed could use same JTAG connector then this problem is solved.

But another problem is that chip developer has different implementation of JTAG state machine though instruction set & signal are same.

Simpler version is that we cannot have common JTAG for all chip unless all chip provider agree to use common logic.

Please correct me if I am wrong.

 

[mrflibble]

Re: Can we have common JTAG programmer for different devices

Regarding the connector, currently there are plenty different physical connectors used as well as IO voltages. Old old 5 Volt parts are bound to use a different voltage level for jtag than say a modern 1.8 Volt part. And when you mix a few of those, then you have to do things like this.

On the protocol side of jtag however things are pretty standard AFAIK. Not quite sure what you mean by different implementation of the state machine...

 

[pkatiyar]

What I meant by different implementation of state machine, is the way to access the JTAG core of IC or in other words the command set of JTAG.

Added after 2 minutes:

So by standard protocal you meant that if I JTAG connecter and voltage level are common then JTAG device can be exchanged without problem?