Recording Total On-Time and Po

The DS1682 provides a method of counting power cycles, total on-time, and alarm-on match functions
that reduce the amount of processor overhead. Total on-time information is useful in applications from
Hobbs meters to equipment warranty, repair, and maintenance.
The DS1682 contains a 32-bit elapsed time counter (ETC), a 17-bit event counter, and a 32-bit alarm
register. In addition, the DS1682 has 10-bytes of user-programmable memory. The counter increments in
º seconds. The ETC and event counter data are stored in EEPROM at the end of each event.
In this example, the EVENT input is driven by a DS1233-15 EconoReset. A Shottky diode and capacitor
provide the energy necessary to allow the DS1682 to store the data to the internal EEPROM when VCC
goes away. An 8051-type processor is used to read the registers and transmit the information to a display
via a serial port. An LED is included in case the alarm function is required.
A schematic of the circuit is shown in Figure 1. Software for initializing the DS1682 and reading the
registers is show in Figure 2.