Features: Records the total time that the Event Input has been active and the number of events that have occurred
Elapsed Time Counter to monitor event durations with quarter second resolution
Built in 32 bit non-volatile Total Time Accumulator Register (34 years)
Non-volatile 17-bit Event Counter records the total number of times an event has occurred
Programmable 32 bit non-volatile alarm trip point to trigger Alarm# output
Alarm# output to alert the user that the total accumulated time limit has been reached
Calibrated, Temperature Compensated RC time base (accurate to 1% typ)
Stores the contents of the Elapsed Time Counter with the previous total and increments the event counter at the end of each event or power down
Reset Enable bit to allow the device to be cleared to zero, if desired
10 bytes of write protectable EEPROM user memory
Write Disable bit to prevent the memory from being changed or erased
Anti-Glitch filter will prevent noise spikes from triggering false events on the Event Input
2-wire serial communication
Wide power supply range (2.5V 5.5V)Pinout
SpecificationsVoltage on Any Pin Relative to Ground -0.3V to +6V
Operating Temperature -40°C to +85°C
Storage Temperature -55°C to +125°C
Soldering Temperature See J-STD-020A specificationDescriptionThe DS1682 is an integrated elapsed time recorder that will provide the total amount of time that an event is/has been active since the DS1682 was last reset to zero via the 2-wire bus. When the total time accumulated is equal to the preset alarm trip point and the polarity bit is set to a zero, the Alarm# output will become active to alert the user, or with the polarity bit set to a one, the Alarm# output will become inactive when the values match. This is ideal for applications such as monitoring the total amount of time that something is turned on or in operation, how long something has been used, or the total number of uses since the last calibration or repair.
The DS1682 uses a calibrated, temperature compensated RC time base to increment an elapsed time counter while an event is active. When the event becomes active, the contents of the non-volatile Total Time Accumulator register are downloaded to the Elapsed Time Counter (ETC) and as the event continues, the ETC is incremented in quarter second increments. When the event becomes inactive or the power is removed, the DS1682 will increment the 17-bit non-volatile Event Counter register and put the contents of the ETC into the 32-bit non-volatile Total Accumulated Time register which can hold up to 34 years of active event time. A storage cap may be required on VCC to provide enough power to store the value in the ETC to the Total Time Accumulator register if power is taken away at the same time the event ends.
When the 32-bit non-volatile Alarm Trip Point register is programmed to a non-zero number via the 2-wire bus and the AoR bit in the Configuration register set to a zero, the Alarm# output will be enabled and the DS1682 will begin to monitor the values in the ETC for the programmed value in the Alarm Trip Point register. Once the number in the ETC is equal to or greater than the value in the Alarm Trip Point register, and the polarity bit is set to a zero, the Alarm# output will become active to alert the user, or with the polarity bit set to a one, the Alarm# output will become inactive when the values match. The DS1682 will activate the Alarm# output by pulling the pin low four times at power up, when the alarm becomes active, or when the Alarm# pin is pulled low and released if the AOS bit is set to a 1. If the AOS bit is a 0, the Alarm# output will be constantly low when the alarm is active.
In order to reset the device, the Reset Enable bit or the AoR bit in the Configuration register must be set to a 1. With the Reset Enable bit set to a 1 or the AoR bit set to a 1 with the Alarm# pin held high, the DS1682 can be reset by the Reset command sent over the 2-wire bus. If the Write Disable flag in the Configuration register is set to a 1 by writing the Write Disable command two times, the Configuration registers and Alarm Trip Point register will not be able to be written. If the Write Disable flag is set to a 1, the Total Time Accumulator, Elapsed Time Counter, and Event Counter will be able to be reset, if the Reset Enable or AoR bits have been set to a 1, but the status of the Reset Enable or AoR bits will not be able to be changed since the Configuration register is locked by the WDF being set to a 1.
The Write Memory Disable of DS1682 is similar to the Write Disable and is used to control the writability of the 10 bytes of EEPROM User memory. The Write Memory Disable Flag is also set to a 1 when the Write Memory Disable command is written twice and can not be changed once it is set to a 1. If the Write Memory Disable bit is set to a 1, the 10 bytes of memory will not be able to be written or erased. If the Write Memory Disable bit is a 0, the user will have full access to the bytes with the standard EEPROM write time restrictions. If the Write Disable is a 0, the device is fully writable or erasable except for the User Memory and the Write Memory Disable flag, which are only controlled by the Write Memory Disable command. With both the Write Disable and Write Memory Disable set to 1's, the only inputs that will be accessible are the Reset command if it is enabled, the Event input and the Alarm# input/output. The rest of the part will be read only.
When data is written to the device DS1682, the device slave address will be sent first followed by the address pointer and the desired byte of data. Once a single byte of data is sent, there must be at least 200 mS to allow the EEPROM to update the data.
DS1682 Data Sheet
