May 2004, Issue 166

Embedded Java Controllers

JStamp/JStik SPECIFICS

The first Systronix product I bought was the JStamp+. Although it has the same footprint as the JStamp, it has 2-MB flash memory instead of 512-KB flash memory (see Photo 1).

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Photo 1—Notice the JStamp’s small size. Nevertheless, it has 512-KB RAM and 512-KB flash memory. This is the size of the other Stamp processors, but it’s faster and has more memory than the others.

The JStamp has two power-in pins: one is for regulated 3.3 V, and the other is for unregulated power. It also has an on-board switching regulator. Use only one of these pins, not both.

The JStamp has a pinout that fits in extremely well with the SimmStick form factor. The exact details are available on Systronix’s web site.

Using the JStamp is easy. You can implement the JStamp development kit, or you can easily build a circuit around it. Because you can put 5 V into the unregulated power pin, the JStamp can be easily put into most common circuits. I’m planning on prototyping a board using the JStamp and a few other components to make a complete system.

The JStamp can take either regulated 3.3 V or an unregulated 5 to 14 V. At the maximum speed (74 MHz), the typical current consumption is 57 mA at 3.3 V, or a bit more at 5 V. If using unregulated power, the JStamp can supply 100 mA of 3.3-V regulated power for your applications.

The JStik is a bit of a change from the JStamp (see Photo 2). Although the latter is a 40-pin-wide DIP, the former is a SimmStick board. Not only does it include a faster processor, but also more memory, an Ethernet port, and an HSIO port. It is possible to use the JStik without a SimmStick backplane, either totally stand-alone or by using an alternate connector. Because the power connectors, the JTAG port, and the serial ports are built into the JStik, you can do a lot with the JStik alone. It is definitely an SBC.

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Photo 2—The JStik is a true SBC running embedded Java. I currently use this as the brain of my robot.

The JStik is programmed just like the JStamp. Note that it has almost the same power requirements as the JStamp, except that at its maximum speed it requires 310 mA when running at 103 MHz. This low current consumption coupled with its power makes the JStik an excellent choice for robotics systems.