[quote author=Coding Badly link=topic=131047.msg985596#msg985596 date=1352227412]
Read from this post forward... SoftwareSerial with ATTiny84 using ATtiny library - #20 by Coding_Badly - Microcontrollers - Arduino Forum
I have already read the topic. That TinyISP can be what I need but it is not well documented, it is mixed with a communication channel /protocol called Knock Bang ( GitHub - Coding-Badly/TinyISP: ArduinoISP replacement with: Tiny Debug Knock Bang, Monitor, Tiny Tuner 2, and other amenities ) which I do not really need. Also, few users reported success in using your ISP Programmer / Serial Relay and from the dialogs you had with forum members it looked like you corrected errors as you instructed people how to use the code. Also, searching for TinyISP on the net to get more information I fond an entity called USB TinyISP that seems to be a different thing. The name misleads.
Your TinyISP software needs a good Tutorial (like this one) for using it as: (1) ISP Programmer, (2) Serial Relay Tx, Rx, (3) Knock Bang protocol.
You have worked a lot at that TinyISP, which could be of great value, but forget the most important step, a good help page for it. Honestly, you code is like buried somewhere. There is no evidence that more than 10 people have ever tried to use it.