JTAG(IEEE 1149.1) Interface, query regarding TAP controller place....

[deepen talati]

Lets we have 5 IC on 1 PCB. Generally we place TAP controller in all 5 interfaces and just route signals TMS and TCK which are we have as I/O signal.
Can it be implemented by 1 TAP controller and we can route control signals produced by TAP to all the 5 IC's.
Or in this case routing could become more complex?

 

[rca]

The question is how many signal need between the "master" IC and other ICs.
JTAG is normaly made for that, i mean 5 JTAG in the same PCB board, and the TDI-TDO are chains to be able to access all 5 JTAGs.
Also the boundary scan is here to check the pcb board.

 

[deepen talati]

what do you mean by master IC and other IC?
we need all the 9 control signals generated by TAP controller for each IC on board
so routing of those signals will be difficult to all IC's if we use just 1 TAP controller on PCB?
thats why do we use TAP controller for each IC separately?

Thanks and Regards,
Deepen Talati

 

[maulin sheth]

Hello,

We have to use each controller for each IC.
Because, If you want to do using 1 tap controller, than how you can control the BSR/ IO- Pads inside chip.
TAP controller control over the IO-pads for Instruction Regs and Data Regs. Data regs - BSR are inside the IC.
So we need each controller for each IC, at least.

-Maulin Sheth