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?
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.
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?
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.