markqvist/OpenModem ? reverse-engineered prompt

Build me the firmware for an open source AFSK modem that can run at 300, 1200, and 2400 baud. It should work as a KISS TNC, support AES 128 encryption inside the modem, handle SD card logging, and save packet captures in PCAP format so they can be opened in Wireshark. I also want adjustable input and output gain, support for standard GPS and Bluetooth modules, large packets up to 576 bytes, and a big packet queue so it can keep up with traffic.

Make it compile cleanly from the source here, and include whatever code is needed for the modem control, packet handling, and serial interface. If you need current details from the hardware or protocol docs, look them up online and follow the OpenModem documentation. Please keep it compatible with the existing OpenModem hardware and make sure the default serial settings are 115200 baud, 8N1.