in a program to make a led blink, when a 1 is written to one...

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Question by Pyke
Submitted on 12/20/2003
Related FAQ: Embedded Processor and Microcontroller primer and FAQ
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in a program to make a led blink, when a 1 is written to one of the ports of an atmel at89c2051 microcontroller, say p1.0, i am expecting to see the led come on but instead the led is turned off. When a 0 is written to the port, the led is turned on. The led is connected directly to the port with a resistor in series to the led and Vcc. Thanks

Answer by Wasty
Submitted on 6/15/2004
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Hello, Pyke. Let me start by explaining how digital data works. If there is a 1 written to a port (for instance your serial port on your pc) there will be a possitive charge (+12v), if the port is set to 0, there will be a negative charge (-12). So if you plug the LED in, opposite from what you have it set to now, your light will tun on with condition 1 and off with condition 0. Uh, looks like I'm a few months late. 6/15/2004-12/20/2003 lol

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