Archive for December, 2010

I want to bring the serial port of the TI Panda boards out to be attached to a Avocent Cyclades ACS5032 SCS serial console concentrator, and I want to make it easy for the IS folks to hook it up.  So that calls for a proper cable to be designed and tested.

Took some doing but I’ve gotten a serial DB9 Male to RJ45 socket worked out and tested (Thanks Sean for doing the testing in the DC).  I’m planning on a ribbon IDC style Male DB 9 connector that will plug into the Female DB 9 pin on the Panda board, that will connect to a keystone RJ45 jack.  That will make it very easy to mount 20 of them on the back panel of the rack mount case.  I think the serial port RJ45 keystone connectors will be blue in color and I’ll use white RJ45 keystone connectors to bring the Ethernet out from each Panda board.  Make it easy to tell which are which.

The test ribbon cable I had around was color coded just a random color coded ribbon cable, nothing special. The RJ45 keystone connectors are also color coded, but their code is the standard Cat5 wire code color

The front of a keystone jack

Keystone Jack front view

The back of a keystone jack
The rear view of a keystone RJ45

Ribbon cable straight through adapter wiring to plug RJ45 directly into an Avocent Cyclades ACS5032 SCS RJ45 port:

RJ45A 3 Orange/White	DB9 3 (Green)
RJ45A 6 Orange		DB9 2 (Orange)
RJ45A 4 Blue		DB9 5 (White)
RJ45A 2 Green		DB9 4 (Purple)
RJ45A 8 Brown		DB9 6 (Red)
RJ45A 7 Brown/White	DB9 1 (Brown)
RJ45A 1 Green White	DB9 7 Yellow
RJ45A 5 Blue/White	DB9 8 Blue

Easy enough but also easy to make a mistake (which I did when I read the Avocent Cabling page):

http://www.avocent.com/Services_and_Support/Technical_Support/Cabling_Options/Cabling_Diagrams.aspx#rj45_cyc.db9.xo

So it was a good thing I sent the cable to the data center and had a working Panda board sent there also so the DC gents could test it.  They caught my mistake and fixed it so one more thing taken care of.  I can add this to the cable harness and know it will work. Yea! 🙂

More on case size testing

Posted: December 3, 2010 in Uncategorized

Dragged out an old 19″ rack case yesterday, measured and the width is 17″ across the front, dropped the 10 stack into the case and it was nice to see that indeed there will be plenty of room to route 10 Ethernet, 10 serial and 40 power wires around the end of the stack without bending the Ethernet too much. So the correct long case will fit 2 stacks of 10, for a total of 20 dual core A9 ARM systems into a single 3U case. Nice.

Today I finish up a 9 pin male to RJ45 serial cable and ship it off to the data center for testing. If I get it correct, they will be able to use a straight through RJ45 cable to hook these up to the Cyclades serial console server. Want to get this right before I have 20 cables made into a single cable harness.

Top and Side view of Panda Board/ daughter card 10 stack

Top and Side view of Panda Board/ daughter card 10 stack

I dummied up a cluster of Texas Instruments Panda boards and a daughter card that will control secure booting.  I wanted to test the size and make sure it would fit into the 19″ rack case I’m having built.  Because Panda boards are back ordered I ordered some blank circuit board stock and cut it to the sizes I needed to build the stack.  I managed to get my hands on two dead boards and then cut 8 more Panda board sized blanks.  Then I made up 10 daughter card sized blanks and bolted them together.

The stack measures 14.5″ long, which will fit quite nicely in a 17″ wide case with room for cables to be attached and routed to the back of the case.  I’ve attached some pictures, you can see the 2 dead Panda boards, 8 blanks and the 10 daughter cards blanks that have the odd shape cut out of them to mount closer to the Panda boards,  The cutout allows room for the USB/Ethernet stack and Audio jacks while the rest of the board fits within 1/2 inch of the Panda board for space savings.

It’s fun doing this work but harder then I expected.  Getting the cutouts and the holes drilled into the blank boards correctly was some harder then I expected.

Tomorrow drag out an old 19″ rack mount case and test in the case, but given the actual size I’m not worried at all.