Starter tips please

NETMF & Gadgeteer
1

At a loss with several things. Would appreciate some pointers.
Using CobraIII, Vs2013.
[ol]I’d like to use the cobraIII as a keybaird through the microUSB client. As I understand it, the deployment and debugging should be done thriugh Serial. How is this done and configured, exactly, both software and hardware? I didn’t find any instructions… What if I don’t want debugging, just deployment: Can I stil use the microUSB connection and not the Serial option?
I’d like also to read keyboard keys connected to the USB host. any sample code?
When using the scenario above (not in debugging and deplyment, but actual operation) the power should come from the external power source. What are the DC voltages and currents reccommendations?
If both external and microUSB power source is connected - is this a problem?
[/ol]
Thanks!

2

  1. what you’re talking about there is USB Client. Read https://www.ghielectronics.com/docs/20/usb-client. There should be sufficient info there to help you understand both software and hardware, but perhaps the one missing piece of info is you need to use the MODE pin to go into serial debug mode - if you need more, ask back here. There’s a Keyboard example that explicitly walks you through the keyboard scenario.

  2. USB Host https://www.ghielectronics.com/docs/36/usb-host and has code examples.

  3. you need at least 7v (according to the silkscreen on the Cobra3). Current depends on what you’re using - you can probably get away with a 1A supply with no problem assuming you’re not trying to run a hungry backlit LCD.

  4. not a problem - Cobra will handle it.

Freebie pointer: Looks to me like you may not have scrolled down through the “documents” section in .NET Micro Framework – GHI Electronics so I suggest you bookmark it.

3

Thanks a lot.

I have read the documentation (about the client, not the host, oops) and the questions arose afterwards.

[ol]Indeed, I am talking about the actual how to set the pin, what to set in visual studio and what connectors/hardware is required. The actual code is as shows in the documentation.
Read, learned, applied. Thanks
What are the top levels for voltage and current that the CobraIII can handle? I want to give it all the juice I can get, as not to fail in real time.
Thanks[/ol]

4

@ Gabriel3

  1. Switching to debug mode on the cobra 3 [url]https://www.ghielectronics.com/downloads/man/G120_and_G120E_Datasheet.pdf[/url] page 10; I think the mode pin has to be held low for the Cobra. Additionally, you will most likely need an FTDI connector, since the Serial port that you need to use doesn’t support 12V. So if you use a normal USB to serial adapter, then it may not work (depending on the adapter). It def won’t work if you use the motherboard’s integrated serial port (beware!)

  2. The silkscreen is next to the barrel adapter 7 to 30 volts. However, don’t let the device drive more than 500ma total on all the pins. Bad things can happen with the stability and voltage drops inside the device.

5

Thanks, again.

Seems quite a bit of a hassle. Even more: I have no idea what “the mode pin has to be held low” means de-facto.

Let me put it in other words:
[ol]If I deploy code through USB and Visual Studio, that implements the USB client (and of course receive an error), the program has been deployed to the CobraIII, right? So if I reset the board and make it run independently, it should work?
If I implement the USB client and make the CabraIII act as a keybaord, can it still draw power from the PC it is connected to through the microUSB?[/ol]

Thanks

6

You’re using a secondary function of the controls - so you’re going to see some compromises. Yes, some might say it’s a hassle :slight_smile:

  1. If you intend to iterate on an app, then you need to continue to use serial debug for the deployment of your app. If you didn’t want to use the debugger capabilities in this process (not sure you’d want to, but perhaps until you get a serial module?) it is possible for you to use a switch so that you don’t enable the USB client function unless a GPIO is set, which might actually mean you can safely remove the MODE jumper and reset the board so that you return to USB debugging and then deploy new code, then enable mode debugging again and reboot and have your client app running - do that by reading the state of MODE in your code.

  2. yes, you can still power Cobra thru the same cable you use.

What you need to do to set MODE depends on the hardware. I don’t think the Cobra3 has a mode pin with a jumper that you can just connect and have it work in serial debug mode. You will need to solder headers onto the third row of pads and connect a lead between MOD and GND (they are adjacent). Once you’ve done that and restart the board, your debug interface will be COM1.

7

Thanks a lot.