But this is a safety mechanism to prevent damage to the adapter.A truly smart power system will poll the amount of power available from the source, then modulate the charge current fed to the battery with the inverse of the power drawn by the system itself, in order to maintain a constant power load on the charger. Yes, it’s annoying when the laptop limits its performance or won’t charge when the incorrect adapter is installed. There are a number of people commenting here who do not appear to understand how smart power systems work, because communication between charger and device is an extremely useful feature. This passes power through the board, but uses the MSP430 to send fake data to the computer. After reading the data and verifying the CRC, it could be examined to find the fields that specify power, voltage, and current.Next, a custom PCB was made with two Dell DC jacks and an MSP430. In the four-part series (, ), the details of reverse engineering the communications and building the spoofer are covered.Dell uses the protocol to communicate with the charger, and Xuan sniffed the communication using a MSP430. While this is a good safety measure, ensuring that a compatible charger is used, it also allows the manufacturers to increase the price of their chargers.Xuan built a device that spoofs this identification information for Dell chargers. Genuine chargers communicate with the laptop and give information such as the power, current, and voltage ratings of the device.

Many laptops require you to use a ‘genuine’ charger, and refuse to boot when a knock off model is used. If you’ve ever had a laptop charger die, you know that they can be expensive to replace.

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