User Manual

PoKeys user manual
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7.5. Matrix keyboard
Matrix keyboard is a set of buttons, connected into a mesh. All buttons in a row share one contact,
same goes for each of the buttons in the column. If a button is pressed, a key press is detected with a
periodic scanning of each of the rows and columns. PoKeys devices use digital outputs for setting the
voltage levels on rows and read column voltage levels using digital inputs that already have internal
pull-up resistors, so no external circuitry is needed.
PoKeys devices support matrix keyboards of up to 16x8 in size, simpler 3x3, 4x3, 4x4 and others are
of course fully supported.
Similarly to simple digital inputs, keys of the matrix keyboard connected to the PoKeys device can be
configured as USB keyboard keys. Direct mapping, mapping to macro sequence and triggered
mapping are all supported. Additional alternate function can be used to assign two different
keyboard keys to each of the matrix keyboard buttons. If additional (and freely selectable from the
list of digital inputs) Fn+ input pin is inactive, the default function key is used. If the Fn+ key input pin
is activated, an alternate function key is used instead of the default.
On all devices, the status of key presses of the matrix keyboard can be read using the PoKeys library
commands without the need to setup the mapping described above.
Figure 13: Standard 4x3 matrix keyboard
Figure 14: 4x4 matrix keyboard internal structure
PoKeys configuration software usage
Before any matrix keyboard configuration can be done, go to ‘Peripherals > Matrix keyboard…’, check
the ‘Enable matrix keyboard’ option and select the number of rows and columns. Close the dialog
and continue by selecting column and row pins.