It's my first time to ask question in English,I hope u can understand me.

I want to debug vxworks Image from com,so i #define WDB_COMM_TYPE WDB_COMM_SERIAL
but when the target boot up,I found that: WDB Comm Type:WDB_COMM_END
WDB:Agent configuration failed
and cann't connect target from workbench. why WDB Comm Type is WDB_COMM_END?
bye the way: If I want to debug the Image ,must i boot in TSFS method? can i use ATA method?
sorry for my poor english~~