BB -xM Rev B not writing to some SD cards.

GoogleGroups
21

Nope. Won’t work. You have to power the logic inside the processor as well. This means isloating that pin from the PMIC as well.

Gerald

22

Download the free Allegro viewer from here:

http://www.cadence.com/products/pcb/Pages/downloads.aspx

Then download the Allegro PCB files from here:

http://beagleboard.org/hardware/design

The allegro tool has a nice measurement tool for measuring distances. You could also use the Geber files and a Gerber viewer as well.

Gerald

23

Good detective work! Will someone fix the u-boot to access the card slower? I built u-boot a year ago. But, I do not want to deal with now. My work around is to use high tolerance SD cards.

Don’t border to test your fix on the expansion header. It is because the output voltage is 1.8V. You need to use a voltage translator to shift the MMC IO voltage.

-Eric

24

Hi Andrew,

Now when you can measure the locations, please let us all know:

  1. The distance of the mounting hole centers on the loner and the shorter side
  2. The distance of expansion connector pin #1 from the nearest corner ((x, y)

These measures are valuable for us all expansion board constructors.

I am designing my expansion boards so that BB and my boards face solder
sides to each others. BB has the female socket connector.
This arrangement allows easy access to the components on both boards
and the use of the JTAG.

Thanks for the measures in advance,
siñ

25

I created for my kicad designs symbol and component for BB-xM. The
location of the mounting holes and the main expansion header have been
board-verified, the remaining expansion headers were verified only by
"eyeballing" (but seem to be correct).
Hope it will be helpful.
beagleboard-xm.lib.rename should be renamed to beagleboard-xm.lib
before importing to kicad.
regards,
j.

beagleboard-xm.lib.rename (9.25 KB)

beagleboard-xm.emp (12.8 KB)

26

Thank you for the information!

It would be interesting to know what kind of expansion
boards you have developed.

I have a few HD audio expansion boards for BeableBoard C4:

24-bit 192 kS/s DAC with audio post processing (I/V, filters)
24-bit 192 kS/s ADC with microphone preamplifier
4 channel HDMI selector with I2S audio decoder

The first one is tested and works well, the other two are
in prototype assembly at the moment.

Best regards,
siñ

27

For now it was just a simple level shifter for I2c and a power supply.
I'm going to use BB as an embedded controller in an UAV I'm building
and with this prototype I wanted to verify some ideas about powering
the board from an external power supply and to experiment with i2c.

j.

28

Interesting project - keep me informed on your progress!
I designed and built a 5V/3A switching power supply for
BB. It can take external voltage from any 6 to 24 volt DC source.
If it is for any use to you, I can email the schematics and board lay-out. The board is approximately 2 cm x 3 cm.

siñ