Connect Vivado hardware manager to ZU+ via MASTER_JTAG
I want to connect to JTAG via MASTER_JTAG instead of the PS JTAG pins. From the documentation I believe I should be able to connect MASTER_JTAG to external PS pins and drive those pins with a USB Platform cable II and connect to the ZU+ (In this case a ZU+ Dev kit with ES2 silicon) with hardware manager. Master_jtag is supposed to give the fabric exclusive access to the JTAG pins, essentially replacing the PS Jtag pins.
So I created a bitstream that just instantiates master_jtag and connects it to pins on the dev kit to which I connected the USB Platform Cable II. I'm unable to connect in hardware manager getting an error about no devices found. I connected the platform cable to the PS Jtag pins and was able to connect successfully so I know the platform cable is working (after clearing the bitstream that instantiated master_jtag).
When I am connected to the fabric pins with master_jtag instantiated I observe that TDO is following TDI without delay. It isn't changing on edges of TCK. As soon as TDI change TDO changes. This is not the behavior I would expect. I tried running JTAG at 6MHz and 750KHz.
Should this work? Am I misunderstanding something about MASTER_JTAG? I've reviewed the xapps that deal with programming efuses with MASTER_JTAG but there doesn't seem to be any initialization or unlocking required to get the interface working.