I'm trying to show digits in a 7 segments LCD display using several 74HC595.
I readed some guides about 7 segments with 595, but all the guides are related to 7 segments diodes and not LCD displays wich seem to be different.
I connected the common of the display to GND and each of the segments to the 595 pin, so I expected to get black the segment when the pin of the 595 is set to 1 and transparent when the pin is set to 0.
The code is working OK but I don't get clear digits. Sometimes the segment I want to be black appears to be not completely black but in between connected and not connected. Other times, when I change a digit from black to transparent, it remains in black.
I've been reading and the segment in a LCD display works as a capacitor.
I'm thinking now that the common in the display shouldn't be connected to GND but that I should alternate the common to GND and VCC and when I display a digit, the pins of the 595 may be set to 1 or 0 depending on where is the common tied ( to GND or VCC ), if common is tied to GND the pins would be complementary to the ones if the common is tied to VCC.
What do you think?