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by johnbeetem
Sun Mar 24, 2013 8:33 pm
Forum: General discussion
Topic: Pi Burned Up
Replies: 11
Views: 2148

Re: Pi Burned Up

In my forays inside displays, I've been shocked (psychologically only, fortunately) to see how, in many cases, there are traces and silk-screening on the circuit boards for highly-advisable protection circuit components ... with none of them installed (very common in Dell's absolutely abhorrent El-...
by johnbeetem
Sun Mar 24, 2013 7:20 pm
Forum: General discussion
Topic: Pi Burned Up
Replies: 11
Views: 2148

Re: Pi Burned Up

Static has high voltage (into the tens of thousands of volts), but almost no current, so it wouldn't do any visible damage like that, only internal semiconductor junction kablooey type damage (that's the technical term ;) ). My guess would be that something like a power diode/rectifier in the TV ve...
by johnbeetem
Tue Mar 19, 2013 6:38 pm
Forum: General discussion
Topic: I made a Raspberry PI Laptop
Replies: 840
Views: 388891

Re: I made a Raspberry PI Laptop

These things originally sold for what, $500? The only reason they're popular now is because South Coast Boutique was having a fire sale and letting these things go at $50 each. I'm sure that was at a loss. How much do you think they would realistically charge for this if they resurrected it for the...
by johnbeetem
Mon Mar 18, 2013 5:35 pm
Forum: General discussion
Topic: I made a Raspberry PI Laptop
Replies: 840
Views: 388891

Re: I made a Raspberry PI Laptop

Here's a good image taken under magnification (original shot in TIFF on my iPhone 5 under a magnified ring lamp) of the JHDMI connector and cable fully exposed. There's multiple smaller bundles wrapped in a larger bundle. It looks like all the ground lines (sans DDC/CEC) are tied together, so if yo...
by johnbeetem
Sat Mar 16, 2013 4:05 am
Forum: User groups and events
Topic: Raspberry Jams - Silicon Valley
Replies: 67
Views: 12075

Re: Raspberry Jams - Silicon Valley

... a ValentFx FPGA shield development board, and much, much more. Are those shipping, or is this is a beta board someone was able to score? It's a beta board that Mike has kindly allowed me to try out, and I've just gotten it back from a long, elaborate, circuitous sequence (just like my posts! ;)...
by johnbeetem
Thu Mar 14, 2013 6:07 pm
Forum: User groups and events
Topic: Raspberry Jams - Silicon Valley
Replies: 67
Views: 12075

Re: Raspberry Jams - Silicon Valley

Jim Manley wrote:... a ValentFx FPGA shield development board, and much, much more.
Are those shipping, or is this is a beta board someone was able to score?
by johnbeetem
Tue Mar 12, 2013 5:34 pm
Forum: Staffroom, classroom and projects
Topic: Where to start?
Replies: 4
Views: 1420

Re: Where to start?

I hear that The MagPi is a good place to start: http://www.themagpi.com/
by johnbeetem
Mon Mar 11, 2013 6:13 pm
Forum: General discussion
Topic: Accessing GPIO which is fastest?
Replies: 5
Views: 1498

Re: Accessing GPIO which is fastest?

You can read multiple GPIO pins at the same time, and then shift the bits around to make an 8-bit number. Take a look at the RasPi Hardware Wiki: http://elinux.org/RPi_Low-level_peripherals You do have to be careful sampling ADC parallel output, since if any bits are changing when you sample them yo...
by johnbeetem
Fri Mar 08, 2013 8:11 pm
Forum: General discussion
Topic: I made a Raspberry PI Laptop
Replies: 840
Views: 388891

Re: I made a Raspberry PI Laptop

..When the Pi errors I see the following message in dmesg: New full-speed USB device unmber 70 using dwc_otg device descriptor read/64, error -32 etc. This is observed for all the ports in the Lapdock. I'm hoping some firmware related option allows the Pi to operate with the Lapdock correctly or a ...
by johnbeetem
Thu Mar 07, 2013 11:19 pm
Forum: General discussion
Topic: I made a Raspberry PI Laptop
Replies: 840
Views: 388891

Re: I made a Raspberry PI Laptop

I have a Motorola Droid Bionic Lapdock, with similar issues. I have carefully tested all my cables and made sure power on the pi was up to spec. Using the 'Y' cable I built I see 4.87 volts at the GPIO pins. The problem I was having was that my Pi did not see the Lapdock keyboard and trackpad. Afte...
by johnbeetem
Wed Mar 06, 2013 6:43 pm
Forum: Beginners
Topic: ARM versions
Replies: 6
Views: 4401

Re: ARM versions

I just had to google that answer sounds made up :) http://www.cs.umd.edu/class/sum2003/cmsc311/Notes/Data/endian.html Once you start thinking about endianness, you begin to think it applies to everything. Before you see big or little endian, you may have had no idea it even existed. That's because ...
by johnbeetem
Tue Mar 05, 2013 12:05 am
Forum: General discussion
Topic: I made a Raspberry PI Laptop
Replies: 840
Views: 388891

Re: I made a Raspberry PI Laptop

I picked up a Lapdock pretty cheap from Amazon. Instead of waiting for adapters to get here on the slow boat from China, I'm going to remove the pins from the built in micro-HDMI connector and solder them directly to an HDMI cable that I've cut one end off of. Has anyone done this yet? If so, any t...
by johnbeetem
Mon Feb 25, 2013 9:45 pm
Forum: General discussion
Topic: I made a Raspberry PI Laptop
Replies: 840
Views: 388891

Re: I made a Raspberry PI Laptop

Couldn't try the USB Male to USB Male Cable with anything else. But if that cable would be faulty it shouldn't work with the Windows PC right? Depends on the failure mode. I have heard of cables that worked fine in one USB A port, but not the other, even though other USB devices worked in both. The...
by johnbeetem
Mon Feb 25, 2013 7:52 pm
Forum: General discussion
Topic: I made a Raspberry PI Laptop
Replies: 840
Views: 388891

Re: I made a Raspberry PI Laptop

The Lapdock Keyboad/Touchpad works now all the time with my PC (running Win8 atm) but still doesn't work with the Pi (tried raspbian and raspbmc today). The Pi works with every other USB Device i have, i'll even tried another Pi... i have absolutely no clue what the problem is. Are you still using ...
by johnbeetem
Mon Feb 25, 2013 3:33 am
Forum: General discussion
Topic: I made a Raspberry PI Laptop
Replies: 840
Views: 388891

Re: I made a Raspberry PI Laptop

... I'm think the USB Male to USB Male Cable is faulty gonna try to get another one tomorrow, i have sadly nothing else to test it with atleast nothing i could think of right now. USB male-to-male adapters work nicely, and reduce length of the cables. This is particularly nice for back-powering Ras...
by johnbeetem
Sun Feb 24, 2013 7:47 pm
Forum: General discussion
Topic: I made a Raspberry PI Laptop
Replies: 840
Views: 388891

Re: I made a Raspberry PI Laptop

To power to Pi I'm using a standard Phone Charger Cable (USB/Micro USB) off one of the two USB Ports of the Lapdock works fine, I'm thinking that the Micro USB from the Lapdock is for the Touchpad and Keyboard right? Which would mean that either the USB Male to USB Male Cable, the USB to Micro USB ...
by johnbeetem
Mon Feb 18, 2013 10:10 pm
Forum: General discussion
Topic: Opening the Atrix Lapdock
Replies: 3
Views: 3826

Re: Opening the Atrix Lapdock

There are links to additional photos and Atrix Lapdock resources at the RasPi Hardware Wiki: http://elinux.org/RPi_Screens#Motorola_Atrix_Lapdock It's hard to describe how to get the back cover off. You found the first step, which is removing the three screws under the rubber feet. The cover is also...
by johnbeetem
Sun Feb 17, 2013 6:01 pm
Forum: Staffroom, classroom and projects
Topic: Assembly - any use in teaching it?
Replies: 138
Views: 32799

Re: Assembly - any use in teaching it?

We use large FPGA devices when developing the next generation GPU chips. The whole GPU is testing in FPGA (the boxes are really quite large ie they have wheels, as we need somewhat more than 200k gates) prior to tapeout so we know they 'work' before spending $750k on masks etc. If you're only 200K ...
by johnbeetem
Sun Feb 17, 2013 5:52 pm
Forum: Staffroom, classroom and projects
Topic: Assembly - any use in teaching it?
Replies: 138
Views: 32799

Re: Assembly - any use in teaching it?

Interesting that the Arm compiler from Arm costs a LOT of money - and significantly outperforms (or did a year ago) the GCC compiler in resulting speed of execution and program size. So although Arm do OS [Open Source] the instructions set, it shows that a bit of in-house knowledge goes a long way ...
by johnbeetem
Sat Feb 16, 2013 7:46 pm
Forum: Staffroom, classroom and projects
Topic: Assembly - any use in teaching it?
Replies: 138
Views: 32799

Re: Assembly - any use in teaching it?

In the future, when people have flying cars, all computers will have dual core FPGAs instead of CPUs - these will be capable of re-configuring each other and the memory which will also be a giant FPGA which will allow them to remember what they were doing before you switched them off when you switc...
by johnbeetem
Thu Feb 14, 2013 9:13 pm
Forum: Troubleshooting
Topic: DELL keyboard settings / key ( | & \ ) not recognized
Replies: 5
Views: 2049

Re: DELL keyboard settings / key ( | & \ ) not recognized

There's an item about keyboard mapping in the Troubleshooting Wiki: http://elinux.org/R-Pi_Troubleshooting# ... an_Squeeze
by johnbeetem
Thu Feb 14, 2013 9:07 pm
Forum: Beginners
Topic: Do I need a power hub?
Replies: 2
Views: 582

Re: Do I need a power hub?

The official power spec for a RasPi board, which includes Ethernet and USB keyboard/mouse, is 700 mA. A 100% efficient 3W power supply is only going to give you 600 mA. It's usually recommended to have at least a 1A supply, which is about 5W. Wireless USB dongles sometimes require a lot of power, so...
by johnbeetem
Thu Feb 14, 2013 8:57 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: Standard i2c only connector
Replies: 8
Views: 2439

Re: Standard i2c only connector

I'd suggest using an existing standard, such as Digilent's Pmod (TM) spec. I've never used it myself, and I don't have any relationship with Digilent.

Digilent Pmods: http://www.digilentinc.com/Pmods

License and link to spec: http://www.digilentinc.com/Pmods/licensing.cfm
by johnbeetem
Wed Feb 13, 2013 9:33 pm
Forum: General discussion
Topic: I made a Raspberry PI Laptop
Replies: 840
Views: 388891

Re: I made a Raspberry PI Laptop

Hello, I can't get my lapdock 100 to power up, my RPi is powered on and tested on another system. Can you please describe and give me sources for the cables/connectors you are using to link the lapdock and Pi? There's a section on the Atrix Lapdock at the RasPi Hardware Wiki: http://elinux.org/RPi_...
by johnbeetem
Wed Feb 13, 2013 9:29 pm
Forum: General discussion
Topic: I made a Raspberry PI Laptop
Replies: 840
Views: 388891

Re: I made a Raspberry PI Laptop

My lapdock has arrived, :D and very expensive it was too after customs and ParcelForce had extracted their pound of flesh. :cry: The one thing missing from the teardown video is taking the screen to pieces. I want to mount the Pi to the back of the screen, so being able to disassemble it would be v...

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