I am using an arduino to program an ATiny like in this tutorial my question is how can i send data to my computer on the serial port. Any ideas are welcome.

I don't think the ATtiny45 or ATtiny85 has a serial port. You might be able to port a SoftwareSerial library to work on one of them and use that to communicate with your computer.

Supposing that you could attach that library and so on, or even bit-bang some data, would the internal timer be accurate enough to send good data? And maybe then only at a very slow speed (can S/w Serial do 300bps?).

The internal RC oscillator can be calibrated so that should not be a problem.

SoftwareSerial.cpp has settings up to 115200 baud, even for an 8 MHz clock. Slower rates would be less prone to error but I expect 9600 would be plenty safe.

I understood that: neither SoftwareSerial nor NewSoftSerial works out of the box with an ATtiny. While the ATmega328p and the ATtiny85 share a lot of similarities, there are enough differences that just getting the old software to compile for the new chip is not sufficient.

But someone did it i wonder how ?

Coding_Badly has a TX routine for the 85 and I think someone did the full SS as well.


download link ?

There's a download here

or get in touch with Coding_Badly or have a search for his threads, there was at least one IIRC about the 85/84 core routines.