MagSafe: Where is the charger ID stored

chargingmagsafepower

I'm about to change my power adapter's cable due to the classic cable fraying.

However, according to this, there's data that gets passed around using the 1-Wire protocol.

I only see 2 wires on there.

Is the cable a "smart" cable with a built-in IC, or are all logic and data pieces in the charger brick itself?

Best Answer

The charger's serialization and capabilities are determined by the chip in the Magsafe connector. The Mac also controls the LED, not the charger.

Understanding the charger's ID code

You can easily pull up the charger information on a Mac (Go to "About this Mac", "More Info...", "System Report...", "Power"), but much of the information is puzzling. The wattage and serial number make sense, but what about the ID, Revision, and Family? It turns out that these are part of the 1-Wire protocol used by the chip inside the connector.

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