Touch +5V with the probe end, the LED should become ON, otherwise you either missed the GND and +5V or the LED polarity (the longer lead should connect to the probe).įrom now on, you may safely ignore +5V pin, because it's not required for a proper operation of the serial port, unless you're going to power RasPi from USB port, that's generally not recommended and will eventually fail. make a probe, according to the picture: GND ]-| if you don't see 5V on the multimeter, choose another pin as GND, and measure voltage between the selected pin and other pins. connect multimeter to the GND and touch other pins starting from RED, once you see 5V on your multimeter, you've found the power pins. If you want to be able to find where is +5V, GND, TX and RX pins, you need a multimeter (a voltmeter basically), 1kOhm resistor and a simple LED.įirst you need to find the GND and +5V, most probably these are BLACK and RED, however might be any colour. What should be the correspondence between the colored cable and their usb pinout ?įor example what this correspondence table of the usb console cable should look like:.With an independent tester (ohmmeter, voltmeter. How should I validate each wire's purpose ?
So, based on the following usb pin layout: I wish to avoid using bad cables on my hardware (raspberryPi, Laptop) and burn my equipment. When it is specified ( here) to connect the white and the green wires like this: In fact, the only working setup looked like this: In theory, the cable should be as in A, but turns out to be like B: A APurpose | B BPurpose Having hours of problem and doubts, I found out that my adafruit cable had ".instead of having the pin connections described as they should be they were mismatched so GND is described as TXD, TXD as RXD, and RXD as GDN.".I am not alone, I experienced a similar problem as:
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