Arden’s Status Report for 12/10/22

This past week I focused on reliable transmission between nodes, like last week. Unfortunately,  due to spikes in current from powering the nodes from a laptop’s USB, I kept running into different issues with acknowledgments causing packets to timeout, and the nodes getting stuck in loops where each one waits on the other to transmit…indefinitely. Switching to batteries imparted some robustness in the protocol. Another major change was changing STM to RYLR896 (LoRa module) communications to UART interrupts. By changing the priority of the UART interrupt to be less than the priority of the tick interrupt, the nodes could still maintain a common notion of time while sending commands to the transciever. However changing the code to using interrupts to communicate with the LoRa module required a non-trivial shift of several functions. I also added a reset line on each individual node to reset the LoRa transciever module itself whenever a general reset is performed, and read in the resulting “LoRa ready” command on restart. I also tested the final topology of 8 nodes several times to detect networking bugs.