FEZ Domino

A few months ago now I was drawn to the relatively new Arduino semi-compatible boards capable of running .Net MicroFramework managed code. With a rich feature list I opted for the FEZ Domino and grabbed one from a local supplier. Curious to see how an ARM core would handle the CLR and managed code.

The design of the Domino is very nice. There are key differences between it and an Arduino, particularly on the IO lines. So you need to be wary when using Arduino shields with the Domino.

As for key features, here is a list from the FEZ Tutorial PDF;

1. Lowest cost at available features!
2. Runs Microsoft's .NET Micro Framework 4.0.
3. Uses Free Visual C# 2008 express.
4. Run time debugging over USB or serial.
5. Program in modern managed language.
6. 32-bit ARM processor, running at 72Mhz.
7. FAT file system for storage on SD cards and USB memory devices.
8. Easy upgrades to high end systems like ChipworkX or Embedded Master.
9. The FEZ core, USBizi, is widely used in commercial applications around the world.
10. RunTime Loadable Procedures

After using Microsoft Visual Studio products for over a decade. One beautiful feature is the use of the free Express Edition as an IDE, and single-step debugger! As well as a feature rich class library in the Microsoft .Net MF framework.

My first task was to develop the interface between the SparkFun ROB-09571 Motor Controller and the FEZ Domino. This turned out to be incredibly easy thanks to the breakout of a second UART to the Domino's EXT edge connector. Three female to female connecting wires hooked up TX, RX, and Gnd. The Domino's System.IO.Ports.SerialPort class can then be used to setup and communicate with the Motor Controller. I also hooked up digital pin 10 (FEZ_Pin.Digital.Di10) to the reset line on the Motor Controller. The MotorTest Visual C# solution can be found here (revision r62).

Modified firmware for the Sparkfun ROB-09571

The Sparkfun Serial Controlled Motor Driver contains adequate firmware code for most purposes, but is begging to be tweaked.

The latest version in my GoogleCode SVN repository can be found here (revision r59).

Changes in this firmware are;

• CURRENT_THRESHOLD has been increased from 150 to 300
  
• Motor current monitoring interrupt code now changes the Sense LEDs based on the ADC
• The command buffer has been modified to accept 'b' as a command (Used to start both motors at a specified speed and direction)
• The speed command is now 16 bits. It is decoded into the OCR1 register directly.
• The UART reply from a command now passes back both Sense current readings from the ADC.