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thomaskuhn
0 Posts |
 Posted - 06 Sep 2006 : 09:29:33
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Does anyone know of a simple way to illuminate an LED from the BitsyX board. I would love to have it so that it blinks at power on. Once the system is up and running, the light goes solid.
Thanks,
Tom
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akidder
1519 Posts |
Posted - 06 Sep 2006 : 10:30:21
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Sure. Take a look at the DIO driver, which includes a bit to control the BitsyX LED. You could combine the DIO driver usage with the heartbeat code at topic 264. You could even use the older LED DLL example at topic 1397, though that code is a bit older.
As it currently stands, it is more straightforward to have the LED blink once CE is running, since the bootloader doesn't implement any special LED control during boot.
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thomaskuhn
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Posted - 03 Apr 2007 : 09:55:21
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Just a quick question...
It has been a while and I am JUST getting to this.
I am a software engineer, not an EE, but understand a bit of electrical design. If I was to use the DIO digital IO's, (Not the ADSmartIO IO's), what voltage to these lines run at? Can they drive a LED on their own? As for input voltage, is it 5v? Since these run to the cpu, what overvoltage/overcurrent protection is needed on the line?
Thanks,
Tom
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cbadr
154 Posts |
Posted - 06 Apr 2007 : 17:10:14
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The voltage of DIO pins is 3.3V. There is a series resistance of 1kOhm. That can drive an LED, but it won't be very bright. Your other option is to connect a transistor to the DIO pin to control the LED with an external voltage source. Some LEDs have a built-in transistor. For more on the IO pins electrical properties, you can look at BitsyXb user's manual in topic 2096 sections 4.7.1 and 6.3.9.
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thomaskuhn
0 Posts |
Posted - 09 Apr 2007 : 16:31:11
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Ok,
I am looking into using some sort of LED driver (uln2803 chip or some other buffer chip) Using this for signals coming from the processor seems to make sense.
What about getting signals back into the DIO? It is 3.3V. What current is needed. The device we are making has 4 "modes", and we are using a rotary switch to both turn on the system and select the mode for the system to be in. I have figured that the rotary switch will be 5 position, 2 pole. One pole used to only for getting power to the board, and the other pole to signal one of the four DIO lines which mode it is set to. Well, out power is going to be 7.4V from the battery. Can I simply use a resistor (I have calculated 2k to bring the voltage to 3.3 at 2mA). Is there another way to do this that I am unaware of?
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akidder
1519 Posts |
Posted - 09 Apr 2007 : 18:10:07
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| Hi Tom. Thanks for the updates. Design questions like these are probably best discussed offline, as they're not of general interest to other users. We'll drop you line directly. |
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