STMPE2401 datasheet(27/55 Pages) STMICROELECTRONICS

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STMPE2401

Interrupt system

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9.7

Programming sequence

To configure and initialize the Interrupt Controller to allow interruption to host, observe the

following steps:

●

Set the IER and IEGPIOR registers to the desired values to enable the interrupt

sources that are to be expected to receive from.

●

Configure the output interrupt type and polarity and enable the global interrupt mask by

writing to the ICR.

●

Wait for interrupt.

●

Upon receiving an interrupt, the INT pin is asserted.

●

The host comes to read the ISR through I2C interface. A ‘1’ in the ISR bits indicates

that the corresponding interrupt source is triggered.

●

If the IS8 bit in ISR is set, the interrupt is coming from the GPIO Controller. Then, a

subsequent read is performed on the ISGPIOR to obtain the interrupt status of all 16

GPIOs to locate the GPIO that triggers the interrupt. This is a feature so-called ‘Hot

Key’.

●

After obtaining the interrupt source that triggers the interrupt, the host performs the

necessary processing and operations related to the interrupt source.

●

If the interrupt source is from the GPIO Controller, two write operations with value of ‘1’

are performed to the ISG[x] bit (ISGPIOR) and the IS[8] (ISR) to clear the

corresponding GPIO interrupt.

●

If the interrupt source is from other module, a write operation with value of ‘1’ is

performed to the IS[x] (ISR) to clear the corresponding interrupt.

●

Once the interrupt is being cleared, the INT pin will also be de-asserted if the interrupt

type is level interrupt. An edge interrupt will only assert a pulse width of 250ns.

●

When the interrupt is no longer required, the IC0 bit in ICR may be set to ‘0’ to disable

the global interrupt mask bit.

STMPE2401 Arkusz danych(PDF) 27 Page - STMicroelectronics