In step debug mode,we can see the value of R0,R1..,PC,SP,etc .I want to print them into a file when in step debugging. Is there anyway to get it? thank you!
Use a Debug Function - see the uVision Getting Started Guide. You have read the uVision Getting Started Guide - and worked through the example projects in it - haven't you...?
As Mr. Neil points out, on page 138 of the Uvision manual is an example for printing various things and the LOG command on page 125 can be used to output to a file.