Electronic Design

Lighting A Coldfire With Netburner

NetBurner’s MOD5213 (see Fig. 1) is based on a Freescale MCF5213 32-bit Coldfire microcontroller (see Fig. 2). The microcontroller is at home on a small PCB that plugs into a standard 40-pin DIP socket. An on-board oscillator and voltage regulator means a developer need only supply the basic power requirements and any necessary connectors on a host board to take advantage of the MCF513. This is the case with Netburner’s development board (see Fig. 3), which is included with the development kit. One thing I would like to have seen is a set of insulated feet on the bottom of the development board.

The MCF5213 houses a V2 Coldfire core that runs at 66 MHz. The core includes hardware multiply/accumulate and division support. It has 256 kbytes of flash that starts out with a copy of the µC/OS operating system. The small OS leaves the majority of space for application code. There is 32 kbytes of on-chip SRAM, so your application will need to stay within these limits. Off-chip memory is not an option unless you implement a serial or flash interface using the undedicated I/O pins.

The microcontroller has built-in JTAG that is accessible via the version of the MOD5213 with a small edge connection at one end of the board. This is the case with the development kit reviewed here. A version of the module is available without these pins. That version is more suitable for production environments.

The peripheral complement is very nice for embedded applications. It includes:

  • CAN 2.0B controller with 16 message buffers
  • Three UARTs with DMA capability
  • Queued serial peripheral interface (QSPI)
  • I2C controller
  • Four 32-bit timer channels with DMA capability
  • Four 16-bit timer channels with capture/compare/PWM
  • 4-channel 16-bit or 8-channel 8-bit PWM generator
  • Two periodic interrupt timers
  • 4-channel DMA controller
  • 8-channel 12-bit ADC
  • Up to 33 general-purpose I/O (GPIO shared with other peripherals)
  • The GPIO are 3.3-V ports so don’t connect them to a 5-V TTL device. Fried transistors are not a developer’s choice of food. The on-board voltage regulator will handle anything from 4.5V to 7 V DC. An external power supply is included for the development board, and there are screw terminals available for power connections as well. Two of the serial ports are connected to an RS-232 driver/receiver chip on the development board before being connected to the 9-pin connectors. You will have to provide your own drivers and connectors if you intend to use the CAN support.

    Soft Burn
    Netburner uses the uC/OS operating system on most of its products, including the MOD5270 I reviewed earlier (see “Getting On The Network: Fast” ED Online ID 10580). The Windows-based NNDK (Netburner Network Development Kit) software and IDE (see Fig. 4) is the same as well. The NNDK uses Cygwin to host the GNU development tools. Cygwin can get a little cranky if you need to set up multiple target platforms, but mixing Netburner’s installations is relatively easy as long as you use the latest version for each platform.

    The main difference is that the MOD5270 has an Ethernet interface while the MOD5213 does not. This means all communication between the IDE is handled through a slower serial port. JTAG is an option that is supported, but a JTAG emulator is not included with the kit. A special JTAG cable connector is required to handle the pinouts on the module.

    Installation and setup is very quick and similar to the MOD5270 with the exception of the Ethernet configuration. The NNDK has a couple of manual command line steps in the installation, but they are minor and are only done once. While it’s possible to use other IDEs like Eclipse with CDT support, setup is much more complex. Stick with Netburner’s standard platform if you can.

    Having the µC/OS operating system and Netburner support application pre-installed means that reaching the first development plateau is trivial. Just connect power and the supplied serial cable, run a terminal program (MTTY is included), and you can communicate with the module within minutes. Building and downloading an application from the small set of examples is possible in less than half an hour, including software installation. That takes care of plateau 2.

    Creating my own application using the Netburner Wizard could not be easier. Basic serial support is trivial to implement so hitting plateau 3 was almost a no brainer. If you have an application in mind already and are comfortable with C/C++, then turning out something with practical feedback in a day is quite reasonable. It will take more time to evaluate the peripheral complement than working out the compiler and debugging details that often bring the initial work on other platforms to a crawl.

    Overall I found Netburner’s solution to be very nice. The software on the module is very powerful and part of the package, so it is just a matter of buying and programming modules for deployment. Development is very practical using only the serial interface for most applications, although the ramp up for JTAG debugging will be significantly greater due to the kind of debugging and development this implies. The job will be significantly easier if you are not messing with µC/OS.

    I would not be surprised to see the MOD5213 module showing up in a range of applications from robotics to process control. I am looking forward to moving my little marvel to a new home with wheels.

    Read next review: Sticking It To The Developer

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