Hi all . First of all excuse my english ,it is not my mother language.
I have an rtc ds1307 connected to a breadboard and then to the mega . Sda,scl with 4.7k resistors and another sensor in the I2C. Powering from an ATX PS 5V to the 5V line (In this case works better than the Vin,I don´t know why ) .
I was facing problems in sda line when the RTC isn’t connected staright on the arduino. Plugging it in the breadboard was failing and sending 165:165, or just nothing .
I connected before the capacitor in the Vcc line ,but it didn’t change anything . But it starts working when I connect the oscilloscope !!
I always follow Nick Gammon 's advices and tips , but this time I couldn’t make the RTC works until I put and 1M pulldown resistor and 1uF electrolytic capacitor from SDA to GND.
Do I am making something wrong ? Are there another better solution that I should try?
Thanks for all .