Hello, I have been trying to create a wireless texting pipeline with Ti-89 Titanium calculators. So far i have written some code and set up a circuit to communicate through xbee communication. The calculators can "text" each other without any modification by simply attaching a link cable (2.5 mm audio jack) between the two and running a simple ti basic program. The idea behind this is to just send the pin changes straight over wireless acting as if there was a wire, so there is no need for emulating the protocol which keeps the programming side simple. The ultimate goal will be to have it wireless but for now im just connecting rx and tx of two arduinos to text if the program and circuit will work. The calculators currently fail to communicate with what i have so far and i'm unable to understand why.
I used hardware interrupts to be notified when the pin state changes, and then i send this change over the TX->RX pins to notify the other arduino that it should set it's pin to the state i sent it. I used software serial because i heard that normal Serial will hang in a hardware interrupt routine. With the use of software serial it shouldn't have the same issue as it doesn't rely on hardware interrupts to send the data so i don't think there should be any issues there.
Calc_chat_3.ino (1.67 KB)