https://www.autoevolution.com/pdf/news_attachements/breaking...
This is a story about reverse-engineering the analog circuitry of the Tesla Model 3. Taking measurements on the "12V" line and seeing voltage dips as low as 2V. Watching this voltage-dip propagate over to the 1.65V reference voltage used by the TI and STM32 chips's ADC.
The ADC taking the (assumed 1.65V reference) at only 0.3V, and then how the voltage applied at the pedal mechanism being misinterpreted as 100% depressed (when the pedal remained completely flat), as well as hardware tests on "Pin44" (see page 19) showing how this changing voltage-reference could cause unintended acceleration.
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I know Musk / Tesla stuff is always a hot topic. But this is incredibly detailed electrical engineering, reverse-engineering, and other such factors at play here. I feel like Hacker News is still an ideal place to discuss, even if I know its going to be flamebait.
Please read over the .pdf and skim over the technical allegations on how the Tesla Model 3 reads/interprets voltages from the pedal, and how the ADC its associated voltage-reference could mess up here... at least for the EEs on this site who can follow the discussion.
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EDIT: The overall argument is as follows:
Root cause: high torque required by the power-steering uses more than 300 Amps of current. Tesla Model 3 12V battery can only supply 100 Amps, and the DC-DC converter to the main batteries only supplies 200 Amps. Low-speed turns requiring more torque could cause the 12V line to drop down as low as 2V.
The software calibrates off of a 1.65V reference point. If the software happens to calibrate during this voltage-drip, it will think that the 0.3V (reality) voltage represents 1.65V.
The accelerator pedal outputs 4V when fully pressed and 0.65V when the foot is off. 0.65V vs the 0.3V reference (thinking its 1.65V) will come back as "thought to be 3.5V" nominal, or nearly a fully pressed pedal (!!!). This will be locked in until the next calibration event. And that next calibration event will not happen for minutes.
This could very well lead to the behaviors discussed in videos like: https://www.autoevolution.com/news/what-made-a-tesla-model-y...