as i am getting back to model railroad, and DCC-EX, i have never really be happy with either stacking shields, breadboarding, or soldering the circuits, for these reasons. stacking shields does have limits, and many of them. breadboarding is only for temporary use, and soldering a circuit makes it less future-proof. so in my implementation, i will be using a PC ISA (16-bit) backplane designed for industrial use (BP-14S), and ISA slot prototyping boards. the plan is to connect all pins from an Arduino MEGA2560 to the ISA data pins. that will give me parallel connections to all pins from any slot. so one slot card will have an Arduino MEGA2560 with connection for the LCD display. i will have another card for the motor driver connections, allowing me to more easily swap out motor drivers for testing, or design my own. as i am using an Ethernet connection to connect JMRI, i will use another card for the Ethernet module, allowing me to update as needed, without having to work in the confines of the enclosure (IOW, pull the ethernet module card, make the changes, and plug it back in). i will also make up a few breadboard cards so i can test various circuits, plug them in, and if i am satisfied, hard-solder the circuits to a blank ISA prototyping board. what this will allow me to do, is test various options, see if they work, and if not, i can reconfigure the cards and restore the arduino firmware as needed to get back to a running configuration again, quickly. so as i build my layout, i can keep it in run-able condition, except when testing circuits. on the backplane i ordered (not arrived yet), i may have to remove some passives if there are any on the arduino pins to remove any possible interference from things like a pull down/up resistor network if on-board. this idea will likely create a large system to tuck under the layout, but i plan on building it into a drawer, so i can pull it out to make changes, or if i need to work under the layout in that area. there are power bus lines on the backplane for +12v, -12v, +5v, and -5v. i think the only issue with using these for different voltages is just the power indicator LEDs on each power bus. so i can turn the -12v and -5v LEDs around to change polarity of the bus (no other blocking diodes installed, i don't think). so i can make the -5v bus into a +3.3v bus, and make the -12v into a future positive power bus. this may seem like the most complicated method in existence, and it likely is, but i think it will make experimenting a lot easier, as well as adding custom non-shield components. besides, i like complicated methods. the best news is, i have finally settled on a basic layout design for testing everything, and experimenting with scenery ideas. and i have found good space to build it in, once i de-clutter it that is. in my basement electronics hobby workshop, it is very cluttered with "spare" electronic components that are just crying out for organization. and if i can get rid of my old network server rack, and find someplace else for my drum kit, then i have layout space. the problem with buying electronic components in bulk from China, is storing the extra ones... just have to find time to organize them on my new peg-board. anyway, i look forward to updating as i make progress on my implementation. currently, i am using a MEGA2560 CORE MCU and dev board, with DCC-EX support circuits hard-soldered to the dev board, but it is very not future-proof. hard to update, even though it works currently, it doesn't allow for much experimentation. my thinking is, i want to control track DCC and local sensors/lights/turnouts with the DCC-EX implementation. but beyond a certain point on the layout, it is more convenient to use OpenMRN/OpenLCB/LCC for control of those, as well as control of various scenery automation (street lights, ect) so providing i can get my act together and clean my clutter, i can finally start my layout! I love the possibilities of DCC-EX's present and future, and really enjoy being able to work with the team, if even in a very small part (i could list my contributions, but that would detract from the team spirit ) i will be posting more detailed notes on my own forum (https://www.tjfhome.net/community/index.php?threads/my-dcc-ex-prototype-and-ho-layout.15/) , but as it is so sparse of users, i will post some here too.