8.3.11Interrupt Mask Register (IMASK, Offset 28h) (Master Mode)

The Interrupt Mask (IMASK) Register is a read/write register. Programming a bit in the IMASK Register has the effect of programming the MSK bit in the associated control register. The format of the IMASK Register is shown in Figure 8-14.

Do not write to the Interrupt Mask Register while interrupts are enabled. To modify mask bits while interrupts are enabled, use the individual interrupt control registers.

When a bit is set to 1 in this register, the corresponding interrupt source is masked off. When the bit is set to 0, the interrupt source is enabled to generate an interrupt request.

Figure 8-14 Interrupt Mask Register (IMASK, offset 28h)

15

7

0

Reserved

SPI I4 I2 I0 D0 TMR

WD I3 I1 D1 Res

The IMASK Register is set to 07FDh on reset.

Bits 15–11: Reserved

Bit 10: Serial Port Interrupt Mask (SPI)— When set to 1, this bit indicates that the asynchronous serial port interrupt is masked.

Bit 9: Virtual Watchdog Timer Interrupt Mask (WD)—When set to 1, this bit indicates that the Watchdog Timer interrupt is masked.

Bits 8–4: Interrupt Mask (I4–I0)—When set to 1, an I4–I0 bit indicates that the corresponding interrupt is masked.

Bits 3–2: DMA Channel Interrupt Masks (D1–D0) —When set to 1, a D1–D0 bit indicates that the corresponding DMA channel interrupt is masked.

Bit 1: Reserved

Bit 0: Timer Interrupt Mask (TMR)—When set to 1, this bit indicates that interrupt requests from the timer control unit are masked.

Interrupt Control Unit

8-25

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AMD Am188TMER, Am186TMER Interrupt Mask Register IMASK, Offset 28h Master Mode, Interrupt Mask Register IMASK, offset 28h