SPRUIE9D May 2017 – May 2024 DRA74P , DRA75P , DRA76P , DRA77P
Figure 30-5 shows the functional specification block diagram of the keyboard controller.
Figure 30-5 Keyboard Controller Block DiagramThe keyboard controller detects events issued on any key of the connected keyboard and generates an interrupt to alert the host processor. The built-in hardware-scan algorithm decodes the pressed keys, including multikey combinations.
To reduce MPU software overhead, the hardware performs detecting and decoding in the keyboard controller state-machine. However, hardware decoding can be deactivated so that software handles the scanning algorithm.
The value of the columns output is determined in the KBD_COLUMNOUTPUTS[8:0] KBC_REG bit field. To activate a keypad row-column connection, the corresponding bit must be 0b0.
The following sections describe subfunctions and subfunction interactions (control and data paths).