- Re: How to get it to read the keyboard matrix
- 06 May 2015 12:27:05 pm Permalink
I have recently come up with the idea of doing this on my own, and got discouraged when I realized that the keyboard matrix was part of the main chip. I started googling to see if anyone else had had this idea before me, and I found this thread. Earlier, you (KermMartian) mentioned that it would be possible to get the RPi to read the matrix. I am confused on how this would work.The matrix (like most keyboard matrices) is arranged with rows and columns. To read the matrix, you repeatedly put voltage on a single row (or column), and read all of the columns (or rows). For example, if you have rows A-D and columns 1-3, like on a telephone keypad, you could put voltage on column 1 and read rows A-D to see if any key in the first column was pressed. Then, switch to putting voltage on column B, and read rows A-D again. You need a total of (R+C) GPIO lines, with (say) all of the Rs configured as output and all of the Cs configured as input.
Another alternative is what Tari has suggested that I do for my TI-87 project (which is relevant, and which you should check out), where I may use a microcontroller to act as a keyboard controller for my Raspberry Pi clone.
Also, sorry for using the necropost.It's not a terrible necropost, and you chose the right topic for it. No worries.