SAMD21 DCC++ Command Station

[dcutting]

I recieved the boards for a new command station in the mail yesterday, and I've successfully put one together and tested some of the main features. Here it is, the SAMD21 command station:

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For those unacquainted with the work that I've been doing on this project (mostly on trainboard), here's the specifications. This board basically functions as a modernized, all-in-one solution to DCC, with some extra features baked in.

- Microchip (ex-Atmel) SAMD21 Cortex-M0+ processor, clocked at 48MHz. It has 32K RAM, which is 16 times the amount of the Arduino UNO and 4 times the RAM of the Arduino MEGA. It is fully compatible with the Arduino platform and is the same chip used on the Arduino ZERO and many of the MKR line of boards. It is essentially the modern equivalent of the Arduino UNO's processor, the ATMEGA328.
- Espressif ESP8266-based WiFi module. Software support is still in the works, but should be ready in the next month.
- Texas Instruments DRV8874 motor driver on the main track supplies 5A continuous and 6A peak current with built-in overcurrent limiting, in addition to the software current limiting already built into DCC++
- Texas Instruments DRV8876 motor driver on the programming track supplies 3.5A peak to the programming track, but is limited in software to 250mA. Can instead be spec'ed with the DRV8874 for booster station operations.
- Built-in railcom detection circuit available on both the main and programming tracks.
- External 256K EEPROM (the SAMD architecture has no internal EEPROM available).
- Expansion headers that allow for addition of LCC, Loconet, CMRI, and S88 shields to the board, or a shield that turns this board into a booster station, complete with railcom detection.

I've been working to create a library version of DCC++ that works on both the classic Arduino plus motor shield combination and on this new board, and I hope to have that ready for others to test later this week.

I will be offering assembled and tested boards starting sometime in June.

[thomasjmdavis]

This sounds like a solution for my situation- where a 2 amp Arduino motor shield was not likely to be sufficient for the several ABBA lashups I want to run (if I ever get the layout built).

If I understand, this is functionally a 5 amp version (less the umpteen pins I don't use anyway), compatible with DCC++ (or will be once you get the software tweaked). 

I, for one, will be watching with interest. 

One note- I tried the link below your signature, and got a "403" error.  Which will make it difficult to order these when you get them on the market.

Glad you posted here.  I do check Trainboard periodically, but missed the thread on this.

[dcutting]

If I understand, this is functionally a 5 amp version (less the umpteen pins I don't use anyway), compatible with DCC++ (or will be once you get the software tweaked). 

Essentially, yes. Little bits like railcom and wifi make it more capable than the original DCC++, plus there is more memory on the chip so you can have as many cabs on the track as you could reasonably want.

www.cescalemodels.com is the website of the company I ran a number of years ago, that got shut down after I lost interest in the hobby after high school. I've had to start from scratch, the new company is called Wasatch Scale Models. I don't have a website for it up just yet.

[timwatson]

I am in on this project. I was in the middle of making a stand-alone dcc++ 5+amp mini ATX power supply system. This sounds like a perfect solution. Let me know and I'll help you test. I have a rework station if I need to solder anything.

[skent]

This is so cool!   Nice looking board, too! 

I always prefer matte black over white soldermask, but it looks pretty sleek in this application.   

Do you have any plans to make this design open sourced?  I'd love to build up one of these myself.

-S

[dcutting]

This is so cool!   Nice looking board, too! 

I always prefer matte black over white soldermask, but it looks pretty sleek in this application.   

Do you have any plans to make this design open sourced?  I'd love to build up one of these myself.

Thanks! I don't plan to make it open source for now. But at the price point I'm considering, it would cost you far more to build your own.

[skent]

Definitely ping the group if you make this open sourced.  I'd love to spin up a tweaked version of my own! 

-S

[dcutting]

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