During Apple’s iPhone 5 unveiling event, they announced a new and revised dock connector with only eight contact pins, which is significantly smaller than the 30-pin connector used on all previous iPhone generations. When announcing the new and revised connector, dubbed Lightning, Apple briefly mentioned that it’s “all digital“. However, they were incredibly vague as to what that actually means.
Over the weekend, a developer by the name of Rainer Brockerhoff examined the Lightning connector and believes that it’s “adaptive”. According to Brockerhoff, Apple was able to drastically reduce the number of pins thanks to a recent breakthrough that allows the connector to automatically sense the type of device it’s plugged into. Moreover, certain chips appear to be embedded in the Lightning connector cables that allow it to intelligently assign different functions to the pins so that it can adapt and use the limited number of pins for multiple applications.
- The device watches for a momentary short on all pins (by the leading edge of the plug) to detect plug insertion/removal.
- The pins on the plug are deactivated until after the plug is fully inserted, when a wake-up signal on one of the pins cues the chip inside the plug. This avoids any shorting hazard while the plug isn’t inside the connector.
- The controller/driver chip tells the device what type it is, and for cases like the Lightning-to-USB cable whether a charger (that sends power) or a device (that needs power) is on the other end.
- The device can then switch the other pins between the SoC’s data lines or the power circuitry, as needed in each case.
- Once everything is properly set up, the controller/driver chip gets digital signals from the SoC and converts them – via serial/parallel, ADC/DAC, differential drivers or whatever – to whatever is needed by the interface on the other end of the adapter or cable. It could even re-encode these signals to some other format to use fewer wires, gain noise-immunity or whatever, and re-decode them on the other end; it’s all flexible. It could even convert to optical.
Also, according to a map of the pins on both sides of the Lightning connector cable that Double Helix Cables provided to AppleInsider, the connector’s adaptiveness is required for the cable to function properly when inserted in either orientation.
“Take top pin 2 for example,” he wrote in an e-mail to AppleInsider. “It is contiguous, electrically, with bottom pin 2. So, as the plug is inserted into the iPhone, if you have the cable in one way, pin 2 would go into the left side of the jack, flip it the other way and the same pair of pins is going to match up with the other side of the jack (as the electrical contacts in the iPhone’s jacks are along the bottom).”
The fact that numerous adapters are necessary to connect different accessories also furthers the theory that the Lightning connector is adaptive – there are chips in the adapters that reassign the pins to recognize what’s being connected and adequately support said connection. Additionally, because it’s adaptable, the Lightning connector may be capable of evolving to support new technologies in the future.
Stay tuned for additional coverage on Apple, the iPhone 5 and the new Lightning connector.