JTAG switch IC instead of multiple connectors

[shaiko]

Suppose I have a PCB with a dozen devices that support JTAG scanning/programming.
I want to avoid chaining all the devices in a typical serial JTAG chain because I'm afraid of possible conflicts between them.
The trivial (but rather inelegant) solution will a dozen JTAG connectors - one connector for each JTAG capable device.

But I was thinking - is there somekind of "JTAG Switch" that can be used together with only one JTAG connector and multiplex it to the correct device according to the data input to the TDI port ?

 

[marce]

**broken link removed**
I will reply in more detail later,it can be done but care must be taken with the clock and its routing, you will probably have to use a clock buffer and simulate the clock lines, they will require terminating carefully, dependant on the PCB layout and routing topography.

 

[shaiko]

Sure it has - like any critical net...have you used such a device in one of your products ?
Is is transparent to the host PC or the firmware must be changed to operate in such a configuration ?