Hi all, I'm new to this group and I'm hoping someone could please help with this issue. I'm trying to interface a 4x4 matrix keypad to Atmel's AT91EB55 board. The issue that I'm facing is that this board does not have a keypad port but it does have many ADCs on it. I'm also trying to limit the number of IOs I have to use.
This keypad is the common 4x4 keypad; that is, you provide voltages to the columns (or rows) and then scan the rows. Anytime a button is pushed, a short takes place and one of the four row pins goes high.
I have looked into a resistor network that will give me unique voltage values such that I can input them to the ADC to give me a unique digital output. This didn't work too well for me as a couple of button's voltages were too close to differentiate; this was also because I only have access to 5% resistors.
Would someone be able to help me out with this? Thank you very much!