SAMD21 Command Station

David Cutting May 27, 2020

  1. David Cutting

    David Cutting TrainBoard Member

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

    IMG_20200526_215625.jpg

    For those unacquainted with the work that I've been doing on this project, here's the specifications:
    • 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.

    David
     
  2. wvgca

    wvgca TrainBoard Member

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    how much do you expect the finished boards to sell for ??
     
  3. David Cutting

    David Cutting TrainBoard Member

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    I'll have a price point later this week, I'm still working with PCB suppliers to get the final quote for assembly. I'm hoping to keep the price around $50-75 per board for the first run. Keep in mind that since it's a first run the cost will be higher because of setup fees and the low quantity.
     
    Last edited: May 27, 2020
  4. David Cutting

    David Cutting TrainBoard Member

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    Hey everyone! Happy Friday!

    I'm happy to announce that my new online store is active and that the SAM Command Station is available for sale!

    https://wasatchscalemodels.com/products/sam-command-station-mk1

    I'm running a batch of 25 boards to start, and I expect they'll be back and ready to ship in 4 weeks' time.

    David
     
    Atani, David Clemson and KC Smith like this.

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