WARNING: [Labtools 27-3123] The debug hub core was not detected at User Scan Chain 1 or 3.
Resolution:
1. Make sure the clock connected to the debug hub (dbg_hub) core is a free running clock and is active OR
2. Manually launch hw_server with -e "set xsdb-user-bscan <C_USER_SCAN_CHAIN scan_chain_number>" to detect the debug hub at User Scan Chain of 2 or 4. To determine the user scan chain setting, open the implemented design and use: get_property C_USER_SCAN_CHAIN [get_debug_cores dbg_hub].
1、确保选取的debug时钟是free-running的,即一上电就有的时钟,不依赖于其他控制逻辑触发才能产生的时钟,时钟是在set up debug时选的,如果不手动选择,工具默认会选择各个debug信号的同步时钟;
2、选取的时钟频率也有要求,印象里在仿真器默认设置下,debug时钟不能低于25Mhz;