Meanwhile let's examine what exactly happens while polling:įirst, we can see a long interval (~1.1 milliseconds) when the level is just high and nothing else is happening:Īpparently that time is used to charge internal HiFive's capacitor - the energy from it will be then used to power-up its internal logic chips At some point the device will grow tired of this endless stream of failures and stop it. But since we didn't connect any accessory, the polling obviously fails. You'll see something like this:Īs you can see, Tristar polls each ID line by rotation - one after another. Right after that start sampling (any rate from 2 MHz and up should be fine). Take a logic analyzer, a Lightning male-to-female passthrough breakout board, some accessory (normal Lightning to USB cable would fit just fine) and of course some device with Lightning portįirst connect logic analyzer's channels to both ID lines of the breakout (pins 4 and 8) and connect the breakout to the device, but do not connect the accessory just yet: Let's sniff the negotiations between Tristar and HiFive.

NXP CBTL1612Ax - Hydra used since iPhone 8/X and apparently everything else that supports wireless charging ( x - number of generation)įrom now on, I'll only use the term Tristar, but keep in mind that it will also mean Hydra as well, as they are very similar in the most of aspects that are gonna be covered in this text.

There're multiple generations of this one ( x - number of generation)

NXP CBTL1610Ax - second-gen Tristar used since iPhone 5C/5S and apparently everything else that doesn't support wireless charging.

NXP CBTL1609A1 - mysterious first-gen Tristar used in iPod nano 7 - source.

NXP CBTL1608A1 - first-gen Tristar used in iPhone 5 and iPod touch 5.

TI THS7383 - first-gen Tristar used in iPad mini 1 and iPad 4.

There're 5 major Tristar/Hydra variants known to me: The most significant change appears to be a support of wireless charging, but that's to be verified: Hydra - is the new variant of Tristar used since iPhone 8/X. Basically, it's a MUX:Īmong many other things, its main purpose is to communicate with Lightning male connector once one was connected - detect orientation and detect Accessory ID and route internal interfaces like USB, UART and SWD accordingly This is certainly true in my cable’s case as I can only charge and sync my iPhone from one side of the cable as other ones doesn’t work at all making the problem particularly annoying.Tristar - is the integrated circuit embedded in every device shipped with Lightning female port. In many cases when the pin becomes black, one side of the lighting cable stops working.

You are welcome to comment below about the result, if you give it a try. We haven’t tested his solution of cleaning the cable with alcohol so can’t confirm if it works. He goes further by suggesting to clean the cable with alcohol, which may make the black side of the cable functional again. Since the electric current is able to jump between the plates easily, this overtime causes the copper to erode, making the pin appear black. The likely cause for this is due to a capacitor charging and drawing more current for a fraction of the second. When the connector is plugged into the iPhone or iPad’s lighting port, there can be a small spark gap that happens when the cable is connected with the device. He explains that the pin or the ‘terminal’ either has a positive or negative voltage connection. According to the user it is a common electrical phenomenon. Luckily another Reddit user who introduces himself as an electrical engineer explains the reason behind 4th pin turning black from gold. Why Fourth Pin On Lightning Cable Becomes Black

Turns out it is something that is quite common and many people have seen lightning cable corrosion judging by the respondents on the Reddit post. After reading his post and looking at the picture that he shared of his cable, I looked for one of my older iPhone cables that had the similar black spot. Today I stumbled upon a Reddit post in which a guy asked the community why does his lightning port’s 4th pin has turned black. Over the years we have all had lightning cables that have shown burn marks and black pin. Have you ever had a lightning cable whose 4th pin (or 5th depending on which side you are counting from) turns from golden color to black? If yes, then you are certainly not alone.

Lightning cable