I have a custom board containing a NVIDIA Tegra TX2. I want to debug this board with my Lauterbach module. However, I do have problems to connect to this board. I hope you can support me a bit.
Next to this custom board I have an official Jetson TX2 dev-board, together with the example scripts from Lauterbach I can connect succesfully to this board. When I do an IDCODE read via SYStem.DETECT I get an IDCODE belonging to ARM Ltd. which indicates for me that CoreSight is selected (NVJTAG_SEL=0, ARM_JTAG)
When I try to connect to this custom board, I cannot get a JTAG connection when NVJTAG_SEL=0. I need to set NVJTAG_SEL=1 in order to be able to read an IDCODE. The IDCODE returned via SYStem.DETECT is an IDCODE belonging to NVIDIA, which for me indicates that NVJTAG is now activated (NVJTAG_SEL=1, NV_JTAG).
For once I assumed that maybe the jtag efuses are preventing me from connecting to this device; but that doesn’t seem to be the case:
sh-3.2# cat /sys/devices/3820000.efuse/jtag_disable
- What is the difference between ARM_JTAG and NV_JTAG? When would I use which option? The TRM is not clear on this topic.
- What is preventing me from doing debugging on the custom board? The fact that I can read the NVJTAG IDCODE indicates for me that the connections are OK, the efuses are also not preventing any access? Any idea?