DS1678 Real-Time Event Recorder

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The user can write only to the RTC, control registers, and user NV RAM. The rest of the memory map is

read-only from the user’s perspective. During an event-log mission, all the memory is read-only. A write

terminates the mission. If there is an event being recorded when the mission is terminated, the event

finishes being recorded before the mission is stopped, and the values in the MIP and ME bits do not

change to zeros until the mission is complete.

During an event-log mission, memory locations 30h and above are not accessible to the user to avoid data

collisions from a user read and an event being logged at the same time. If the user tries to read a location

with an address greater than 2Fh during a mission, the value returned is 00h.

Table 3. DS1678 Event Elapsed Time Duration

ADDRESS

REGISTER

0000

Event 1 Elapsed Time from Last Event Counter LSB

0001

Event 1 Elapsed Time from Last Event Counter MSB

0002

Event 2 Elapsed Time from Last Event Counter LSB

0003

Event 2 Elapsed Time from Last Event Counter MSB

0004

↓

07FB

↓

07FC

Event 1023 Elapsed Time from Last Event Counter LSB

07FD

Event 1023 Elapsed Time from Last Event Counter MSB

07FE

Event 1024 Elapsed Time from Last Event Counter LSB

07FF

Event 1024 Elapsed Time from Last Event Counter MSB