The CPU will not bo to idle mode by itself, It was "INSTURCTED" to do it.

So just post your test program again. (I mean the "WHOLE test" program, not just the comm. part).

You mentioned you cannot see the data, but you now you can see it with your "echo program".

Could you tell us what do you mean by not "NOT SEEING".
You cannot see it with the CRO?
or you can see it by the CRO but not PC?

Please state clearly your test setup as well..

Cheers

LL