Connecting your computer - The Mission Pinball Framework (2024)

Connecting your computer to the Stern SPIKE CPU node

Related Config File Sections:

• hardware:
• spike:

There are at least 3 options to connect a computer running MPF to theSPIKE CPU via a serial connection.

1. USB to USB Null Modem Cable
2. USB to Serial Adapter
3. Using two USB to Serial Adapters

OPTION 1: USB to USB Null Modem Cable

Probably the cleanest and easiest method is to purchase the USB to USBNull Modem Cable. With this cable, you can plug one end into the USBport on your computer and the other end into one of the two USB ports onthe SPIKE board. On a Windows computer, use the Device Manager todetermine which COM port the cable has been assigned by Windows. Updateyou machine configuration with the correct COM port (example, COM5).

spike: port: COM5

Null modem cables used to be a common way to connect two computerstogether. This is the most expensive solution at about \$50 USD. Howeverit looks just like a USB cable. The only vendor that has the USB to USBNull Modem Cable is the FDTI company.

https://ftdichip.com/products/usb-nmc-2-5m/

This particular cable also provides faster data transfer rates (up to 3MBaud) than Options 2 and 3.

OPTION 2: USB to Serial Adapter

The second method is to purchase a USB-to-serial adapter and connect itto the DBGU header (CN2) on the SPIKE CPU node. The problem you may haveis that not all SPIKE boards have the header soldered onto the board. Aheader is essentially a 6 pin socket that the adapter can plug into. Ifyou do have the header at location CN2, great! Read on.

Ok, you have a header on the SPIKE board. Simply purchase an inexpensiveUSB to serial adapter and plug it in. There are lots of them, most forless than \$10, and they're all pretty much the same.

Some examples that should work (though we don't guarantee it and we'rehappy to hear feedback or recommendations):

https://www.amazon.com/FICBOX-CP2102-Serial-Downloader-Arduino/dp/B01CU12324/https://www.amazon.com/HiLetgo-CP2102-Module-Serial-Converter/dp/B00LODGRV8https://www.amazon.com/HiLetgo-Ft232rl-Serial-Adapter-Arduino/dp/B00IJXZQ7Chttps://www.adafruit.com/products/3309https://www.sparkfun.com/products/12731https://www.sparkfun.com/products/13830

Make sure you have a 3.3v adapter (or that your adapter can be set for3.3v).

Connecting using DBGU

Connect the USB serial adapter to the DBGU header (CN2) on the SPIKE CPUnode.

Pins are marked GND, RX, TX. You do not need more than these.

Unfortunately, this header seems to be missing on some revisions ofSpike. You can solder it in though. However, it does not contain anyflow-control pins to it will not work at higher baud rates (up to 400kroughly).

OPTION 3: Connect using two USB-Serial Adapters

Newer versions of the SPIKE CPU node do not have a connector attached tothe CN2/DBGU header. The newer board is the same, but you see a blankspot instead of the plug-in connector attached. If you do not want tosolder a header onto the SPIKE board then you need to go back to Option1 or use this option. Soldering on the SPIKE board is risky if you lackexperience with a solder iron and will likely void your warranty.

For this option, you can buy two USB serial adapters and then use theUSB connection on the SPIKE CPU node.

The one you connect to the SPIKE CPU node needs to have an actual FTDIbrand chip because the FTDI drivers are included in the code on theSPIKE board. The second adapter for your computer can be any brand sinceit's easy to install whatever drivers it needs on your computer.Whatever serial port appears on your computer when you plug in thisadapter is the port name you'll use in your machine config.

These two adapters will have connectors or headers on them that you needto connect together. Connect the "RX" (receive) from one to the "TX"(transmit) on the other and vice-versa. Also connect the grounds(possible labeled "GND") together. It's probably a good idea to twistthe wires together to reduce interference, especially if your wires aremore than a few inches long.

In addition to above you should also "CTS" to "DTS" and "DTS" to"CTS". This will allow you to enable hardware flow control which isessential at higher baud rates (up to 3M).

The following diagram illustrates how everything fits together:

You've essentially created a null modem cable as described in Option 1.This option may be a little cheaper but the solution is far less elegantand stable.

What if it did not work?

Have a look at ourSPIKE troubleshooting guide.