The next experiments would be quite rich with analog signal measurements. Thus I needed a better way to display and analyze waveforms with my toy-scope.

There's an open source firmware for the DSO-138. Although it seems inferior to the original FW, it prints the acquired data through the serial port by feature, so iv'e gone with it.

The guide for firmware update requires shorting some jumpers, but I want more control so I can switch FW at any point with minimal effort. It came out like this:

To go into UART bootloader I simply toggle the 2 switches and reset the device.

To acquire and display it all I made a little python script, which can be found in my github.

The resulting graphs really make visibility much much better - now I know how much info is lost for the tiny display.

Let us measure the negative voltage generator of the DSO itself, as it's waveform is quite rich in detail.

This:

turn into this:

With zoom:

So much details can be suddenly observed. This will be helpful in the next steps.