Specifications

11-1
Watchdog (WD) Timer
The watchdog (WD) timer peripheral monitors software and hardware opera-
tions, and implements system reset functions upon CPU disruption. If the soft-
ware goes into an improper loop, or if the CPU becomes temporarily disrupted,
the WD timer overflows to assert a system reset.
Most conditions that temporarily disrupt chip operation and inhibit proper CPU
function can be cleared and reset by the watchdog function. By its consistent
performance, the watchdog increases the reliability of the CPU, thus ensuring
system integrity.
All registers in this peripheral are eight bits in width and are attached to the low-
er byte of the peripheral data bus of the 16-bit CPU.
The only difference between the ’240x WD timer and that on the ’C240 is the
lack of real-time Interrupt capability.
This implementation of the WD timer generates it’s own watchdog clock locally
by dividing down the CLKOUT from CPU.
Topic Page
11.1 Watchdog Timer Features 11-2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
11.2 Control Registers 11-4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
11.3 Watchdog Control Registers 11-8. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Chapter 11