DS1832

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The second function the DS1832 performs is pushbutton reset control. The DS1832 debounces the

pushbutton input and guarantees an active reset pulse width of 250 ms minimum. The third function is a

watchdog timer. The DS1832 has an internal timer that forces the reset signals to the active state if the

strobe input is not driven low prior to timeout. The watchdog timer function can be set to operate on

timeout settings of approximately 150 ms, 600 ms, or 1.2 seconds.

OPERATION - POWER MONITOR

The DS1832 detects out-of-tolerance power supply conditions and warns a processor-based system of

active for a minimum of 250 ms to allow the power supply and processor to stabilize.

OPERATION - PUSHBUTTON RESET

The DS1832 provides an input pin for direct connection to a pushbutton reset (see Figure 2). The

pushbutton reset input requires an active low signal. Internally, this input is debounced and timed such

the pushbutton reset input is released from the low level.

OPERATION - WATCHDOG TIMER

the predetermined time period. The timeout period is determined by the condition of the TD pin. If TD is

connected to ground the minimum watchdog timeout would be 62.5 ms, TD floating would yield a

are the microprocessor address signals, data signals or control signals. When the microprocessor

functions normally, these signals would, as a matter of routine, cause the watchdog to be reset prior to

timeout. To guarantee that the watchdog timer does not timeout, a high-to-low transition must occur at or

less than the minimum times shown in Table 1. A typical circuit example is shown in Figure 4.

The DS1832 watchdog function cannot be disabled. The watchdog strobe input must be strobed to avoid

a watchdog timeout and reset.