8.4.5Interrupt Request Register (REQST, Offset 2Eh) (Slave Mode)

The internal interrupt sources have interrupt request bits inside the interrupt controller. A read from this register yields the status of these bits. The Interrupt Request Register is a read-only register. The format of the Interrupt Request Register is shown in Figure 8-21.

For internal interrupts (D1, D0, TMR2, TMR1, and TMR0), the corresponding bit is set to 1 when the device requests an interrupt. The bit is reset during the internally generated interrupt acknowledge.

Figure 8-21 Interrupt Request Register (REQST, offset 2Eh)

15

7

0

Reserved

TMR2 D1 Res

TMR1 D0 TMR0

The REQST Register is set to 0000h on reset.

Bits 15–6: Reserved

Bits 5–4: Timer 2/Timer 1 Interrupt Request (TMR2–TMR1) —When set to 1, these bits indicate the state of any interrupt requests from the associated timer.

Bits 3–2: DMA Channel Interrupt Request (D1–D0) —When set to 1, D1–D0 indicate that the corresponding DMA channel has an interrupt pending.

Bit 1: Reserved

Bit 0: Timer 0 Interrupt Request (TMR0)—When set to 1, this bit indicates the state of an interrupt request from Timer 0.

8-32

Interrupt Control Unit

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AMD Am186TMER Interrupt Request Register REQST, Offset 2Eh Slave Mode, Interrupt Request Register REQST, offset 2Eh