Can somebody help me how to enable P1 of TUSB3210 as input. If I set P1=0xff,I see P1 appear 0xff,so I confuse set it as input and set all P1 pin to '1'.
What does the Data Sheet say? Standard 8051 ports do not have a "data direction" like some other processors - see: http://www.8052.com/forum/read.phtml?id=88984 However, you need to check the Data Sheet for your TUSB3210 to see if it does have any "advanced" options beyond the standard 8051...