hello all,
        I want to connect the MTi to overo air(expansion board is summit) using ttyS0, for changing the logic level,
 I have made a circuit and it works  as the communication(both read and write) between the summit ttyS0
and the PC ttyS0 very well. I have bitbaked the program of MTi and installed it in overo air. If I connect the MTi
to overo by usb-hub, and run the program it works. When I connect MTi by ttyS0, run the program,
 it does not work. But on the scope,I can see the signal send from MTi (1.8v). and use
#cat </dev/ttyS0
it shows the same as connecting the MTi to PC by ttyS0, of course, connecting to PC, the program works well as
connect to overo by usb-hub.
Anyone had the same case? Anyone  help?

regards