ET-ARM Stamp

I recently got an ET-ARM Stamp (a very wide DIP-format board with an ARM microcontroller on board). I haven't done anything exciting with it yet, but I will as soon as I can think of something! Some notes about the thing:

First, it's normal that there appears to be a solder bridge between two of the pads on the 49..64 side. Before I even turned it on, I was worried that my board was damaged, but it was just fine.

I'm a bit disappointed with futurlec for the amount of documentation that is available on their website. Some more is furnished on a CD (file listing), however.

They seem to be selling the product of the Thai company The URL on the board's silkscreen ( doesn't work for me. offers a slightly more powerful board in the same footprint, the lpc2138 with 32KB RAM and 512KB flash, but futurlec don't seem to carry it. Even if you don't read Thai, you might benefit from the diagrams (including a schematic of the et-arm stamp) in their manual.

I built a compiler from scratch on my Ubuntu system, using gcc, newlib, and newlib-lpc. There were kinks in the build process. Basically, gcc seemed to require that newlib be built already, and vice versa. I finally used some combination of "make -k" and copying header files into place. Unfortunately, my notes are poor.

I've been using newlib/newlib-lpc for some compiles, and no library for others. The commandlines I use are shown in Makefile.common.

I'm using lpc21isp to program the board. The main "gotcha" seems to be that you have to supply a filename to program even if it won't be used (e.g., for -termonly). It's also an annoyance to constantly specify the baud and clock, so I use a helper script to do it. Baud rates over 38400 don't work for me, but whether this has to do with lpc21isp, my USB-RS232 adapter, or with the ARM itself I don't know. To start the programming sequence, it's necessary to press the buttons on the stamp (hold LOAD and click RESET).

I got the stamp board at the same time as the stamp itself. Again, not a lot of documentation! There's a power jack, labeled 7-12V AC/DC, for which I happened to have a compatible AC adapter (12VDC). There's also a 2-pin connector for 7-12V AC/DC, as well as an input for regulated +5V.

I've never used JTAG, but there's a 20-pin connector on the stamp board. From what I've read this would work with a wigger clone and the right Linux software.

As you'd learn from the documentation included source code, the LCD is hooked up for 4-bit mode on P1.16 through P1.21. One of the demo programs displays to the LCD just fine, though I haven't used it from software of my own yet.

What's missing? So far, I've only wished for a USB interface instead of RS232 serial. Much better to have a CP210x (or ftdi232 or whatever) and a USB "B" connector on board than a special serial cable and a level shifter (which in my case just hooks to another level shifter and then to a USB port). They could also hooked up some of the control lines and eliminated the need to manually press the LOAD and RESET switches while they were at it.

Entry first conceived on 7 March 2006, 3:33 UTC, last modified on 15 January 2012, 3:46 UTC
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