hello! i find the problem which i debug my Project with Keil Software(V7.05). it's no Serial 2, can't useing Dual Data Pointers,and can't useing other special features of VERSA1-B(VRS1001-C20B) MCU when i Start Debug my my Project,Although i can select the VERSA1-B(VRS1001-C20B) device in Project -> Option for Target "Target1" ->(device list) ->Goal Semiconductor ->VERSA1-B(VRS1001-C20B). it's looks like the standard 8052 CPU. who could tell me How could i do for useing my VERSA1-B(VRS1001-C20B) MCU's special features ? With best regards ! BTW:The VERSA1-B(VRS1001-C20B) DataSheet at : http://www.goalsemi.com/VERSA1-B_Datasheet.pdf