DS1616

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During a datalog mission, the DR bit is cleared to a logic 0 when a data conversion has been initiated and

is set to a logic 1 upon the completion of the conversion. Likewise, the DR bit is cleared immediately

after the Read Data command is issued and is set to a logic 1 upon the completion of the conversion.

DATA LOGGING

When the DS1616 datalogging function is enabled, the device is said to be on a “datalog mission” until

the datalogging is stopped.

During a datalog mission, temperature and/or ADC samples are successively written to the Datalog

memory pages. These memory pages are located at addresses 1000h to 17FFh.

The end user can program the DS1616 to record data from all four data channels or just one channel.

Channel selection is determined by the setting the Channel Select bits (CS0, CS1, CS2 and CS3) in the

Control 2 register to the appropriate states. A 1 in the CSx bit will enable the channel and allow the

results to be reported, while a 0 will disable the channel, prevent its data from being recorded, prevent the

data from being reported by the Read Data command, and set the contents of the memory location for the

Current Data register corresponding to that channel to a constant value, all 1s for the thermal sensor or all

0s for the ADC channels.

When 3 or 4 data channels are selected, the first data sample is written to address location 1000h, the

second is written to address location 1001h. The address is incremented with each additional data

sample, with samples alternating between the enabled channels. The second sample is always measured

immediately after the completion of the first measurement with the third and forth samples following the

second. The order of the sampling is the same as the order of the Channel Select registers. CS0 will be

sampled first, if it is enabled, followed by CS1, CS2 and CS3 if they are enabled. Any disabled channels

will be skipped. A total of 2048 registers have been reserved for datalog data, providing a total of 512

samples for each channel.

When three out of the four channels are enabled, a fourth byte of all 0s will be recorded in the Datalog

Memory after the three bytes of data from the enabled channels in order to allow the data to rollover and

remain in the correct positions. Without the extra, unused data byte, the channel’s memory location

would switch between even and odd sections, and there would be two extra bytes at the end of the first

682 samples recorded in the Datalog Memory. This would cause the first rollover to occur in the middle

of a datalog for the three channels. This would make finding a given channels data very difficult after a

few rollovers after a few rollovers.

When two data channels are selected, the first data sample is written to address location 1000h and the

second is then written to address location 1001h. The address is incremented with each additional data

sample, with samples alternating between the enabled channels. The second sample is always measured

immediately after the completion of the first measurement. A total of 2048 registers have been reserved

for datalog data, providing a total of 1024 samples each channel.

If just one data channel is selected, the entire datalog memory is dedicated to that one channel and

therefore a total of 2048 samples can be recorded.

A datalog mission can be initiated via two different methods: by a host instruction over the serial

interface or by a pushbutton input. When the SE bit in the Control 1 register is cleared to a logic 0, the

mission. When the SE bit is set to a logic 1, the pushbutton method of starting a mission is enabled.