The past couple weeks were spent attempting to get the RS 485 connection working in a dummy system. The system consists of two Arduino Unos utilizing Max 485 chips to convert a UART TTL signal into RS 485. Presently the goal of the dummy system is to allow for two participant devices to send full-duplex data to the controller device. Getting RS 485 to work in half-duplex mode between two devices first has been the first major milestone to hit, and unfortunately I have not managed to work out all of the kinks in this system. First I had to actually learn how the RS 485 protocol works, and how using UART with Arduinos works. After setting up a basic example circuit I attempted to initiate a data transfer between the two Arduinos. I was able to get one device to send data to the other, but I was not able to implement half-duplex communication for some reason. After multiple days of debugging I eventually narrowed it down to a hardware issue with one of the Unos itself, and after swapping it out for a different Uno I have managed to receive data with both devices. However, there is currently a sync issue somewhere in either the code or the circuit that was not present with the initial broken Uno, so my current task is to debug that. I intend to spend much of tomorrow debugging this and hope to have half-duplex communication working in my dummy system by the end of the day.
This week we as a team revised our schedule. We realized that we’d over and under-budgeted for some of the tasks on our schedule, so we made some changes now that we’ve had time to flesh out our project a bit more. As such, I am sadly slightly behind schedule. The hardware issues with one of my Arduinos significantly slowed me down, but I am not concerned about making that time back. There is plenty of slack time for my portion of the project, so I’m not particularly worried about this setback.
By the end of this week I intend to have half-duplex communication working between the boards in my dummy system, and then establish the same two-way communication individually with both the Jetson <-> Due bus and the Micro <-> Due bus. By the end of the following week I hope to have the entire three-way system implemented.