STMPE2401TBR datasheet(20/55 Pages) STMICROELECTRONICS

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System controller

STMPE2401

20/55

7.3

States of operation

The device has three main modes of operation:

●

Operational Mode: This is the mode, whereby normal operation of the device takes

place. In this mode, the RC clock is available and the Main FSM Unit routes this clock

and the 32 KHz clock to all the device blocks that are enabled. In this mode, individual

blocks that need not be working can be turned off by the master by programming the

bits 3 to 0 of the SYSCON register.

●

Sleep Mode: In this low-power mode, the RC Oscillator is powered down. All the blocks

which need clocks derived from the 32KHz clock will continue getting a 32KHz clock. In

this mode also, individual blocks can be turned off by the master by programming the

bits 3 to 0 of the SYSCON register. However, the master needs to program the

SYSCON register before coming into this mode, as in the sleep mode, the IIC interface

is not active except to detect traffic for wakeup. Any activity on the I2C port or Wakeup

pin or Hotkey activity will cause the device to leave this mode and go into the

Operational mode. When leaving this mode, the I2C will need to hold the SCLK till the

RC clock is ready.

●

Hibernate Mode: This mode is entered when the system writes a ‘1’ to bit 5 of the

SYSCON register. In this mode, the device is completely inactive as there is absolutely

no clock. Only a Reset or a wakeup on IIC will bring back the System to operational

mode. All I2C activities are ignored.

Caution:

Hotkey detection is not possible in hibernate mode.

Figure 5.

State of operation

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