STMPE1801BJR datasheet(52/60 Pages) STMICROELECTRONICS

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Keypad controller

STMPE1801

52/60

Doc ID 17884 Rev 3

11.5.3

Keypad wakeup from Hibernate mode

The keypad controller is functional in Hibernate mode as long as it is enabled before

entering the Hibernate mode. It will then wake the system up into operational mode if a valid

key press is detected.

An asynchronous detection of the keypad column input activity is turned on during the

Hibernate mode. If any key activity is detected, the system wakes up into operational mode

for the de-bouncing of the key press to take place. If a valid key is detected, the system

stays in operational mode; otherwise, the device goes back into Hibernate mode.

11.5.4

Keypad controller combination key interrupt

The keypad controller (KPC) can be programmed to exit from Hibernate mode if a unique

combination keys is detected. These combination keys of up to 3 keys are specified in the

KPC combination set 0-2 registers.

There are 2 combination key operation modes. The modes can be set in the

COMB_KEY_MODE in the KPC_CTRL_HIGH register. In ‘OR’ mode, the device exits from

Hibernate mode on ANY of the 3 keys specified in the KPC combination set 0-2 registers. In

‘AND’ mode, the device exits from Hibernate mode ONLY if ALL of the 3 keys are pressed.

The sequence of the key pressed in not relevant as long as the 1-3 keys specified in the

KPC_COMB_KEY registers are detected, the KPC will exit from Hibernate mode and

interrupt the host. All the "active" keys must be pressed and held together, for the combi-key

interrupt to be generated.

If any other keys (beside those specified in the KPC_COMB_KEY_N registers) are pressed,

it would be considered an invalid combination and no interrupt will be generated.

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