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Novice Alex

Member Since 27 Feb 2011
Offline Last Active Nov 28 2012 11:12 PM
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Posts I've Made

In Topic: Introducing Netduino Plus 2

12 November 2012 - 03:33 PM

Hi Chris, Firstly, I like to congrats on your latest N+2 which I have been waiting for a long long time. Just like to check is there any other reseller other than the 3 listed on your site? So far, looks like only Amazon has stocks, but it "refuse" to do shipping to Singapore. Any chance from other resellers? Regards, Alex Chan

In Topic: SD File corrupted

24 September 2012 - 11:29 PM

Hi Chris, I remember the SD card corruption happens after around 7 days of "burn test". I have been trying to do "hot swap" for newly design PCB to see any effect on the system reliability. Then it starts to hang the whole N+. After putting in a few debug statement, it came to know that it was hang during the writing to a data text file. I have tried to do file deleting on the SD card on my PC, but it still exists after I do a screen refresh. So, no choice but to reformat it. I suppose it can be caused by the loss of power during the writing (while doing the "hot swap"), but how can we recover from there if such incident happens again, given that this system will be deployed to remote sites out in the sea, so it will be quite trouble to access. From my attached class, is there any potential problem that you can foresee? Thanks in advance. Regards, Novice Alex

In Topic: How to debug program without using VS?

13 September 2012 - 11:45 PM

Hi Chris, I am running in the latest .NETMF 4.2 release recently. But I am running the Netduino firmware on the N+ board as I need the SD card feature but without the Ethernet capability. Currently, the board is power by an external source +12Vdc and also connected the usb cable to my computer for easy deployment when needs arise. May I know where can I change the deployment port to COM1 or COM2? Is there any setting that I need? Regards, Novice Alex

In Topic: Protect or encrypt program Code in N+

04 September 2012 - 11:48 PM

Hi Novice Alex,

Let me start with a few tips and let others chime in as well...

Since .NET code is a close approximation to C# source, you may want to look at a program like Dotfuscator which will help keep your code from getting decompiled easily. NETMF HEX files are already one step away from standard MSIL DLLs, but in theory they're still MSIL.

My second recommendation is to add a security key to your deployment file (using MFDeploy) and using an "RTM" version of NETMF firmware to lock out any debuggers This will help make sure your board uses signed firmware.

We use direct flashing and custom boot loaders for commercial projects...but we can search around for some documentation on MFDeploy's signing/encryption methods if needed.

Chris


Hi Chris,

Noted. Just like to know that steps for the MFDeploy, is it that I only need to selected the "encrypted" exe and it will deploy to the correct segment of the N+? So far, I only use MFDeploy for the firmware upgrades procedures.

Also for the security key, how and what are the steps on implementing it?

Sorry for my ignorance and thanks for the advice in advance.

Regards,
Novice Alex

In Topic: Ways to read large (>12Kb) text files from SD card

25 August 2012 - 12:36 AM

It all depends on the file format. Since you're writing daily stats? You could do several things:
- Make records an X amount of bytes large
- Create a file format that works with data blocks
- Create an index

I have too little information right now to really be able to help you out.

Hi Stefan,

That's sound like a good idea. Since each records is fit by the format [mins since 00:00 of the day] | [Double value with 3 decimal place]. I can fix string format for both. And use ReadBlock to do it. However, need to do some testing to see whether it improve in processing.

in fact, currently when I read back the full content, I will then pass the full file content (as string) back to the caller for further parsing and then determine the require range (report time start to end) and accumulate the total value in the field (2) - Double.

Regards,
Alex

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