STC8H3K64S2 makes LCD12864USB voltage and current capacity table

Although I have a USB table for Juwei on hand. But the cost is more than 20. Because during this period of time I was fiddling with the voltage and ammeter of the microcontroller. I just happen to have a 1.4-inch 12864 POS disassembled LCD screen on hand. The cost is about two yuan. Including the microcontroller and other software, the cost should not exceed 10 yuan. If you think about it, do it. Experience DIY fun and sense of accomplishment. It takes a lot of time, but just play with electronic waste and entertain yourself. After many days of debugging and pattern making, it was finally successful. Except no shell functions up to its own requirements. The size is also very compact. It can measure the maximum voltage of 30 volts and is suitable for most USB chargers with super fast charging protocols. The maximum current is about 10 amps. It can detect input, D+, D- three voltages and one current value at the same time. By observing the D+D- voltage. You can roughly tell what the agreement is.
Compare with Juwei's product color screen USB table.