Delete comment from: Ken Shirriff's blog
I'm curious as to the voltage that genuine MacBooks use for the 1-wire comms. The DS2413 is specified between 2.8 and 5.25V. Using an MSP430 running at 3.3V, I've had great success toggling the LEDs on original adapters, but not a single aftermarket replacement works: the LEDs won't come on.
A teardown reveals that the circuit inside is entirely different. Probably, they are using a cheap microcontroller to bit-bang the 1-wire bus on a GPIO pin. I haven't checked the voltage on the zener yet. (With apologies for my terrible drawing:)
https://imgur.com/a/qRUy1Rg
Could someone with a multimeter and a nearby macbook check the DC reading between ground and the middle (1-wire) pin on their laptop's power socket?
Jan 21, 2019, 7:57:22 AM
Posted to Teardown and exploration of Apple's Magsafe connector