I've created a DCC++EX system using Adafruit Feathers for DeadRail. Its all documented here: https://largescalecentral.com/t/dcc-ex-control/80964 It starts out using the Arduino Mega, then by post 37 I am starting to use the Feather. At post 57 I start a tabletop version. Post 63 demos a possible HO scale version for DeadRail. The tabletop version is finished by post 75, the DeadRail version starts at post 77. A prototype is working by post 91, after that 10 or so posts show its assembly.
I was working with someone who had the code working on both the Feather and a Metro. Was that you? I am not sure if it was deadrail. But I thought we had what we needed to run the full EX Command Station, generating the DCC waveform and needed to merge it in.
I was working with Fred Decker, if that's you, then yes. Once I got the code stable I was off to "the next thing" (extending the track, carriers, etc. etc. etc.) Haven't looked at the code in quite a while, haven't had to, it just works at this point.