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Uart boot has now been figured out on the LX

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looks like the pad thickness has changed from the didj to the lx

Maybe to reduce to the cost per board? Less surface area to plate?

sd pins and cart detect have longer pads now?

before this was only for the power pads

Pad size comparison, same magnification used on the microscope and angle

Sparkfun:

We actually had to retire this item because it is totally unsupported by the Arduino IDE.

http://www.sparkfun.com/commerce/product_info.php?products_id=8789

I can get it to work fully with just a few lines add to boards.txt

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Before:

Notice how the surface isn’t smooth with the plates in.

After:

How did I do that?

First I used a layer of plastic model glue to secure the panels in place. Once the glue had dried I sanded as much as i could to make the panels flat with the case surface. first with course sand paper 40 grit then move my way up slowly to 250 grit.

Next I applied a layer of primer paint. let it dry then sanded it down with 250 again.I then applied some epoxy to the cracks with a razor blade to make sure that the surface was as smooth as possible. sanded smooth then applied another layer of primer. once the primer was dried for a day i took some very fine wet sand paper and wet sanded the case till it was super smooth.

now it looks like there were never panels to begin with :)

After a ton of probing and trace fallowing I have come up with this schematic :)

M14 is the piggy backed roms only one side of the pins of the chip are used

IC2 is the TM5200

Table of WTF magic

now for power im using this circuit

work fine with my arduino, now to get to coding and building an small amp for the sound out

I acquired a Ti speech synthesizer module today cheep to experiment with :)

According to this old data sheet I found of the speech chip TMS5200.pdf this should be easy to interface to a Didj or arduino!

Oddly there is a second rom chip stacked on top of the original in parallel with all pins soldered to??

So I took the unit apart and removed the connector carefully to reuse it.

cleaned up the pads and lightly filed the board to fit the connector.

then carefully modified the connector so it would slide onto the board better

Next: power and bus management

just plug my new box into their usb port :-D

made with the Adafruit arduino enclosure :)

yes that is right I am building a 12 bit core memory unit :-D

the ferrite beads I purchased were so small that only 1 strand of wire wrap wire would go though. now to test this one bit i have assembled already

There was a slight bug found with the resistor used for the card detect pin for the Micro SD card hot swapping.

Originally a 300k resistor was used to pull down the SD_D3 data line.

It was found that this resistance is too high to use and will not allow for proper hot swap detection of the Mirco SD card.

Though some testing it was found that there is a 100k pull up resistor inside the LX that totally throws off the detection resistor value and makes it not work.

The Solution: Replace the 300K resistor (R4) with a 82.5k resistor.

All boards made from today on will feature this new update.

This is what the new resistor looks like

I am trying to figure out how to ship out resistors to those who already purchased a DJHI and would like to try to fix this.

There have also been reports of random shorts and strange behavior when the DJHI is plugged into a LX or Didj. I looked at the boards very closely and found a small routing problem that happens on some boards.

It is some times very very hard to see with the naked eye but under the microscope you can see some debris of the connector from the routing going a little too far. General use of the DJHI can cause this little flake of metal to flatten out and cause a short.

Solution: if you are experiencing random glitches and non power on issues, take a razor blade and CAREFULLY remove the debris from between the ends of the pads. As of today this will be checked for for every board built from now on.