Analog Pins for drive LEDs
#1
Posted 26 July 2012 - 02:54 AM
#2
Posted 26 July 2012 - 04:04 AM
Hi Guys,
As I have exhausted all the Digital Pins for all my pulse counter and communication, now only left with the Analog pins untouched. May I know is there any way I can use the Analog pins for driving a LED (for machine status) purpose? also can it be configure to use to detect button press input?
Thanks in advance.
I have recently used a few of the analog pins for similar reasons as yours. I can confirm you can use them as TTL output pins and almost certainly as TTL inputs.
Just ensure the maximum forward current through each LED doesn't exceed 25mA(maximum pin current).
#3
Posted 26 July 2012 - 06:05 AM
Just ensure the maximum forward current through each LED doesn't exceed 25mA(maximum pin current).
You might want to double check the limits per pin on the Netduino Plus page as 25mA looks to be too large a current draw.
Regards,
Mark
To be or not to be = 0xFF
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#4
Posted 26 July 2012 - 08:07 AM
The A0 to A5 pins can be used as GPIO with interrupt capabilities, just like the D0 to D13 pins.
As Nevyn pointed out though, the max. current is important:
max current: 8 mA per pin
digital pins 2, 3, 7: 16 mA per pin
analog pins 0-3: 2 mA per pin
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#5
Posted 27 July 2012 - 10:22 AM
#6
Posted 27 July 2012 - 11:07 AM
Hook the output from the Netduino to a transistor and use that to deliver more power and you should get a brighter LED.thanks for your sharing. Now I managed to light up my LEDs as per normal by setting the Analog pins as output, but as mentioned by Stefan, the output current is limited, so it may not be too bright. Anyway is a good step.
Regards,
Mark
To be or not to be = 0xFF
Blogging about Netduino, .NET, STM8S and STM32 and generally waffling on about life
Follow @nevynuk on Twitter
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