https://drive.google.com/file/d/11pN...uhMMrPdIk/view
I attached a video link where you will see the code failure.


You will see in the ldc 20x4 the negative voltage is displayed very quickly, the lcd will register voltage 12.45 and in the proteus dc voltmeter it registers 12.5V


in the 20x4 lcd it registers a positive voltage of 12.58, it displays normal and in the dc voltmeter of proteus it will register a voltage of 12.6V.
You will see that the decimals record different values of both positive and negative voltages.
I hope that the video can serve you better to see and correct the code.
thank you