Matrix - Keyboard E-blocks2 - BL0138

The keyboard consists of a grid of 3 x 4 switches connected to the E-blocks 2 system.
This way, you will be able to enter numerical and textual data into the embedded system.
The switches are push-button type, they are read by combining the logic level of the columns and rereading the state of the rows.
Only one key can be read at a time.