8.3.5Watchdog Timer Interrupt Control Register (WDCON, Offset 42h) (Master Mode)

The watchdog timer is implemented by connecting the TMROUT1 output to an additional internal interrupt to create the watchdog timer interrupt. This interrupt is assigned to interrupt type 11h. The control register format is shown in Figure 8-8.

The systems programmer should program the timer (see section 9.2.2 on page 9-3)and then program the interrupt control register.

Figure 8-8 Watchdog Timer Interrupt Control Register (WDCON, offset 42h)

15

7

0

Reserved

MSK PR1

PR2 PR0

The value of WDCON at reset is 000Fh.

Bits 15–5: Reserved —Set to 0.

Bit 4: ReservedMust be set to 0 to ensure proper operation of the Am186ER and Am188ER microcontrollers.

Bit 3: Mask (MSK)—This bit determines whether the watchdog timer can cause an interrupt. A 1 in this bit masks this interrupt source, preventing the watchdog timer from causing an interrupt. A 0 in this bit enables watchdog timer interrupts.

This bit is duplicated in the Interrupt Mask Register. See the Interrupt Mask Register in section 8.3.11 on page 8-25.

Bits 2–0: Priority (PR) —This field determines the priority of the watchdog timer relative to the other interrupt signals, as shown in Table 8-3, “Priority Level,” on page 8-15.

Interrupt Control Unit

8-19

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AMD Am188TMER, Am186TMER user manual Value of Wdcon at reset is 000Fh