I've been working with a software serial implementation for Attiny13A ir order to have a debugging tool, in fact it is Nerd Ralph asm routine exactly. Looking the datastream in an oscilloscope looks right, all the timing is precise and repeatable. The problem comes when I connect my serial-usb receiver and I look on the terminal (I tried arduino serial monitor, Putty, and Terminal.exe and all gives the same response).
My program sends ASCII character 48, but always on the PC I am receiving ASCII character 96.
It seems that the serial terminal is missmatching the first LOW bit (the start bit) as part of the 8 bit payload of the message.
I think the circuit and the software is allright, looking on the oscilloscope looks right, so there must be a problem with the adapter or the serial teminal
Any ideas of where this problem is coming from?
Thank you in advance