Hi, I speak Spanish, so I translated it in google
I have a problem with the ADC, the microcontroller PIC16F877A, I'm using 6 analog inputs, AN0, AN1, AN2, AN4, AN5 and AN6, and use AN3 VREF + which is connected to 5Vdc.
4 analog input has a 10K potentiometer, which sends a 0 - 5Vdc. PIC's ADC converts the digital signal input selected and then sends that value for serial port in visual basic 6 program is the formula to convert to the corresponding analog value.
My problem is that there are two entries that have nothing plugged in, and should read 0 volts, but the PC when it displays the information in these channels put random values. also happens when I send 0 volts potentiometers.
also the maximum value that can appear is 5V, and sometimes appears 7.
Another problem is off the microcontroller and the PC sends a data through the serial port, the power LED flashes.