STC12LE5616AD datasheet(128/377 Pages) STC

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The External Interrupts INT0 and INT1 can each be either level-activated or transition-activated, depending

on bits IT0 and IT1 in Register TCON. The flags that actually generate these interrupts are bits IE0 and IE1

in TCON. When an external interrupt is generated, the flag that generated it is cleared by the hardware when

the service routine is vectored to if and only if the interrupt was transition –activated, otherwise the external

requesting source is what controls the request flag, rather than the on-chip hardware.

The Timer 0 and Timer1 Interrupts are generated by TF0 and TF1, which are set by a rollover in their respective

Timer/Counter registers in most cases. When a timer interrupt is generated, the flag that generated it is cleared by

the on-chip hardware when the service routine is vectored to.

The Serial Port Interrupt is generated by the logical OR of RI and TI. Neither of these flags is cleared by

hardware when the service routine is vectored to. In fact, the service routine will normally have to determine

whether it was RI and TI that generated the interrupt, and the bit will have to be cleared by software.

The 2BH interrupt is shared by the logical “1” of SPI interrupt and ADC interrupt.Neither of these flags is cleared

by hardware when the service routine is vectored to. The service routine should poll them to determine which one

to request service and it will be cleared by software.

The 33H interrupt is shared by the logical “1” of PCA interrupt and LVD ( Low-Voltage Detector ) interrupt.

Neither of these flags is cleared by hardware when the service routine is vectored to. The service routine should

poll them to determine which one to request service and it will be cleared by software.

All of the bits that generate interrupts can be set or cleared by software, with the same result as though it had

been set or cleared by hardware. In other words, interrupts can be generated or pending interrupts can be canceled

in software.

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STC12LE5616AD Datasheet(PDF) 128 Page - STCmicro Technology Co,.Ltd