8.3.9In-Service Register (INSERV, Offset 2Ch) (Master Mode)

The bits in the In Service (INSERV) Register are set by the interrupt controller when the interrupt is taken. Each bit in the register is cleared by writing the corresponding interrupt type to the End-of-Interrupt (EOI) Register. See Table 8-1, “Am186ER and Am188ER Microcontroller Interrupt Types,” on page 8-3.

When an in-service bit is set, the microcontroller will not generate an interrupt request for the associated source, preventing an interrupt from interrupting itself if interrupts are enabled in the ISR. Special fully nested mode allows the INT1–INT0 requests to circumvent this restriction for the INT0 and INT1 sources.

Figure 8-12 In-Service Register (INSERV, offset 2Ch)

15

7

0

Reserved

SPI I4 I2 I0 D0 TMR

WD I3 I1 D1 Res

The INSERV Register is set to 0000h on reset.

Bits 15–11: Reserved

Bit 10: Serial Port Interrupt In-Service (SPI)—This bit indicates the in-service state of the asynchronous serial port.

Bit 9: Watchdog Timer Interrupt In-Service (WD)—This bit indicates the in-service state of the Watchdog Timer.

Bits 8–4: Interrupt In-Service(I4–I0)—These bits indicate the in-service state of the corresponding INT pin.

Bits 3–2: DMA Channel Interrupt In-Service (D1–D0) —These bits indicate the in-service state of the corresponding DMA channel.

Bit 1: Reserved

Bit 0: Timer Interrupt In-Service(TMR)—This bit indicates the state of the in-service timer interrupts. When set to a 1, this bit indicates that a timer interrupt request is in-service.

Interrupt Control Unit

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AMD Am188TMER, Am186TMER In-Service Register INSERV, Offset 2Ch Master Mode, In-Service Register INSERV, offset 2Ch