STMPE1601TBR STMICROELECTRONICS [STMicroelectronics], STMPE1601TBR Datasheet - Page 53

• Manufacturer Part Number: STMPE1601TBR
• Description: 16-bit enhanced port expander with keypad and PWM controller Xpander Logic
• Manufacturer: STMICROELECTRONICS [STMicroelectronics]

STMPE1601
Keypad combination key registers
pressed down before the special function key. Hence, when a matrix is reported "key-down"
and it is being held down while the corresponding special function is being pressed, a "no-
key" status will be reported for the matrix key when the special function key is reported "key-
down". If the matrix key is released while the special function key is still being held down, no
"key-up" will be reported for the matrix key. On the other hand, if the matrix key is released
after the special function key is reported "key-up", then a new "key-down" will be reported for
the matrix key, followed by "key-up".
Keypad wakeup from sleep and hibernate modes
The keypad controller is functional in sleep mode as long as it is enabled before entering the
sleep mode. It will then wake the system up into operational mode if a valid key press is
detected.
In the case of hibernate mode, the 'HIB_WK' bit in 'KPC_ROW_msb' register must be set to
'1' in order to enable the system wakeup by means of a valid key press. When this is
enabled, an asynchronous detection of the keypad column input activity is turned on during
the hibernate mode. If any key activity is detected, the system is expected to enter the sleep
mode temporarily to allow a debouncing of key press to take place. If a valid key is detected,
the system will then wake up into operational mode; otherwise, the device will go back into
hibernate mode.
Keypad controller combination-Key interrupt
The keypad controller (KPC) can be programmed to wake up from sleep mode if a unique
combination keys is detected. This combination keys of up to 3 keys is specified in the KPC
combination set 0-2 registers. Note that the sequence of the key press is not relevant, as
long as the 1-3 keys specified in the KPC_CombiKey are detected, the KPC will wake up
and interrupt the host.
If any other keys (beside those specified in the KPC_CombiKey registers) are pressed, it
would be considered invalid combination and interrupt will NOT be generated.
All the "active" keys must be pressed and held together, for the combi-key interrupt to be
generated.
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