One plan would be to use a purpose designed keyboard scanner chip. This would have a serial I2C output that sends data when a button is pressed. There are MANY such chips available.
On Fri, Feb 1, 2019 at 7:05 PM Thaddeus Waldner <thadw...@gmail.com> wrote: > I am in the process of installing a manual control panel on my router, > using a MESA 7i73 pendent card. The panel has a 5x6 button matrix and 16 > LED indicators. I am driving the LED indicators with a pair of 74HC573 > 8-bit latch. I had initially planned on wiring each buffer input to a > corresponding output on the MESA 7i73 > . > However, after mapping out the keys, I discovered that this is not > possible becuase the 23 keys on my panel are arranged in a 5x6 matrix, > which requires that I configure the MESA 7i73 for an 8x8 keypad. This > leaves me with 14 outputs total; 2 short. > > One option that I think I have is to connect the inputs of both latch > chips to the same 8 outputs and use the latch enable on each chip. > > I have no idea how I would implement a latching buffer scheme in the > LinuxCNC HAL. Can anyone help me with that? > > I am using the 74HC573 devices because I have them on hand. Would it be > simpler to use a 74HC154 demultiplexer instead? > > Thaddeus Waldner > > _______________________________________________ > Emc-users mailing list > Emc-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/emc-users > -- Chris Albertson Redondo Beach, California _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
