Bob Alkire's Weblog

I've been working to bring up prototype of a SPOT board based on the Atmel AT91SAM9G20 processor.  This is an ARM9 (ARM 926) that is several generations past the SPOT's AT91RM9200. I've used openocd JTAG to bring up the board and wanted to post the script.[Read More]

The following article voids warranty. Say your SPOT is "bricked" and you've been through the Q&A on the SpotWorld forum. Some folks don't like RMAs, warranty and would rather fix it themselves. This blog is for them.

A non-responsive SPOT with no USB activity can often be recovered by reflashing the bootloader. The SPOT's JTAG interface can be used to install a new bootloader if the old one is corrupted.[Read More]

I have tossed around a number of ideas on how to hook Ethernet to the SPOTs. The AT91RM9200 does have a built in Ethernet MAC and we did bring out the RMII interface with the intention of having Ethernet hooked up someday. The design needed an RMII PHY and 50MHz oscillator and we would have to adapt low level MAC drivers and integrate a TCP/IP stack.

I found an interesting option. When I was at the FIRST competition in Atlanta last April, I met with the Luminary Micro folks about their chips. What interested me the most was a low priced Cortex M3 (ARM) processor with built in Ethernet MAC-PHY.[Read More]

The eSPOT demo board has an Atmel AVR microcontroller (MCU) for LEDs, pushbuttons and general IO. This MCU comes preprogrammed at the factory  and can be reprogrammed in the field with an ant upgrade command. A SPOT owner might wish to change the firmware to either add functionality or do something the eDemo board currently doesn't provide.

The latest Red release of the SPOT SDK will program the eDemo AVR firmware directly and without a bootloader during the upgrade process. The same code that is used to upgrade the eDemo board firmware can be used to load custom firmware into the eDemo AVR. This blog walks you through the steps of downloading a tool chain for Windows and programming a simple example on the eDemo board. It does use an existing java class that is in the Red release of the SPOT SDK and this SDK must be installed on the desktop and the target SPOT plugged into USB for this to work.

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We have a PS3. I got it 'cause it's a great blu-ray player. My son uses it for playing those games. Nevertheless, it will not only play little round discs but movies on a USB stick, or from a "Media Server". The "Media Server" caught my eye - it looked like something that my Solaris NAS box could do.
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In the battery blog I did, I mentioned using a java program to measure internal resistance of the battery. I updated the program and will post the snippets here.

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A while back, I built a home PC with the latest and greatest top o’line graphics card, the nVidia GeForce 8800GTX. This monster was longer than your typical PC card,  took two slots for it’s own cooling and had two independent power connectors to feed it. It was an impressive piece of graphics until I got to Rivendell in my MMORPG and fwoomp, the dreaded blue screen of death (BSOD). [Read More]

On the SunSPOT world forums, there was a query regarding the power consumed by the TI CC2420 radio transceiver. The SPOT has quite a bit going on and the power consumption is very dynamic. The only way I could see to get an accurate reading was to isolate the power into the radio chip. There is a ferrite bead, FB1, in series between the switcher and the radio VDD that could be removed and a milliammeter put in its place.[Read More]

The Sun SPOT, our wireless sensor network device,  is powered by a small rechargeable prismatic lithium-ion battery. This battery is similar to the one found in most cell phones and mp3 players. This is some of the what I learned while designing with this battery. To find out more about the Sun SPOT go http://www.sunspotworld.com or https://spots.dev.java.net. [Read More]

My job at Sun for the past few years has been the hardware lead for the Sun SPOT project. This is a big topic for me and I have a lot of unfinished blogs about it. If you don't know what a Sun SPOT is: go to http://www.sunspotworld.com/[Read More]

Further adventures of a home NAS with Solaris 11. Setting up the time server and upgrading Solaris.

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Random adventures of engineering part 1. Building a home NAS server using Solaris 11 with ZFS at center stage.[Read More]