Serial issue

[CWells]

I've got a 08M hooked up to another uC...if I press a button, the 8M sends a short string with the serout command. When just the grounds are connected, a logic probe shows the signal on the pin, but when I connect the pin to the input on the other uC, the stream isn't there anymore. What gives? Do I need a resistor in the serial line? If so, what value?

 

[Dippy]

What is the mystery uC??? Is it top secret?

Have you connected it to a pin on the uC which is in Output mode?
Or something else...??
Are you 100% sure the other uC is happy and healthy?
Is it powered properly?

If you link it with a , say, 1K0 resistor is the output stream present on your 08M?

If so, it sounds like the mystery uC is dragging it down - like a short.

Can you tell us the uC pinout?
Is it running your own code or someone else's?