Hello Haopen,
In datasheet of TDA8026, interrrupt response is described in detail, see following:
(1)Interrupt line: IRQN pin; open-drain, active LOW output
(2) On page 9 of datasheet
When card insertion or removal is detected on card slot 1, an
interrupt signal (IRQN) is sent to the microcontroller.
(3)On page 10
1. Card insertion on card slot 1 is signalled by the IRQN pin signal being driven LOW.
2. Using the IRQN pin signal, the microcontroller detects the card insertion and drives
the SDWNN pin HIGH to wake-up the TDA8026
3. When the SDWNN pin is HIGH, the IRQN pin is set to HIGH and the analog module is
powered-up. A full power-up sequence is executed by the TDA8026
4. When the TDA8026 is ready, the IRQN pin is set to LOW
5. The microcontroller detects the device interrupt using the IRQN pin and services it
which resets pin IRQN to HIGH
(4)on page 18
When at least one of the PRESL, SUPL, PROT, MUTE and EARLY bits is set to logic 1,
IRQN pin is driven LOW until the status byte has been read. After power-on, the SUPL bit
is set to logic 1 until the status byte has been read and the IRQN pin is LOW until the
voltage supervisor is deactivated.
(5)On page 32
When the DC-to-DC converter cannot act as a step-up converter, an overload alarm is
sent to the digital module and all card slot interfaces are deactivated. This causes the
IRQN line to be driven LOW and the Bank 1 Register 0 PROT bit is set to logic 1.
Sumarry, several functions in TDA8026 will share the same IRQ pin, when interrupt occurs, IRQ pin will be LOW, host will response it, then enter interrupt service routine to handle it, at first routine will inquire interrupt status register to know who generagtes interrupt service requirement, then according to it, perform correspongding handling.
Regards,
weidong
