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Topic: DCF77 library for Arduino - synchronize with atomic clock (Read 17 times) previous topic - next topic

Nachtfalke

I connected the GND and the Vcc of the module with GND and the 5V-pin of the arduino. I tried connecting the signal pin with D2 of the arduino with and without a 10k pull up resistor. With the resistor, the signal on D2 stays at hi. Without the resistor the signal shows the behaviour seen in my attachment. The modules datasheet clearly states a supply voltage range from 1.2 V to 5 V, so there should be no overloading. The datasheet also states a maximum ripple of 10 mVeff. Maybe thats the problem. Does anyone know the ripple of the 5V supply voltage while arduino is connected to my PCs USB-port?

Udo Klein

The datasheet says maximum current 5uA. With a 10k pullup you draw 500uA. You are overloading it. You should try a 1M resistor.
Check out my experiments http://blog.blinkenlight.net

Nachtfalke

Actually the datasheets states an output current > 5µA, but i will try a 1M resistor. Maybe it works. It won't hurt anyway :D

Udo Klein

Yes, but it also says current consumption <100uA. Obviously the >5uA gives you a hint about the capabilities of the module. If it could drive 500uA they would have written it. This kind of module is designed to go into a clock --> low current consumption is a design goal, extended driving capability is not. --> I would be very suprised if it would be able to drive 500uA. This is the reason why I bought one with additional driver transistors.
Check out my experiments http://blog.blinkenlight.net

Nachtfalke

The 1M resistor does part of the trick. The signal doesn't stay at high with the 1M resistor connected, but it shows the same signal sequence as without any resistor, so the signal peaks are still much shorter than stated in the spec :(

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