USB to TTL downloader

1. LED1 is the download indicator light. It lights up when downloading and turns off when it is finished.

      LED2 is the power-on indicator light. It lights up when power is turned on and goes out when power is turned off.

      LED3 is the chip ready indicator light. When it is connected to the computer, it will first light up for about 0.5 seconds, and then go out. When it goes out, it means it is ready.

2. PCB board interface! ! !

     focus

    2.1. I modified the data cable myself because I don’t have a small head at home. If you use it yourself, you must pay attention to changing the interface package to one that suits you.

      2.2. A cold start is required when downloading. You can also unplug and plug in the GND cable after clicking download. If you find it troublesome, you can add a circuit to pin 17 of the chip (which changes to high level when downloading starts) to automatically disconnect and connect to GND.