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[Nate2]

Minor issue, but 4 AAA batteries just to retain the time of day for the clock in the CM15A during a power outage?
The old serial interface only required 2, if I recall correctly.

[Knightrider]

Don't forget that the 4 AAA's keep the programed timers and macros in the interface as well.  I'm pretty sure that mine keeps the program for 48 hours without power.

[Nate2]

Don't forget that the 4 AAA's keep the programed timers and macros in the interface as well.  I'm pretty sure that mine keeps the program for 48 hours without power.

CM15A owner's manual, page 37:
"The Timers and Macros will be stored in the Interface's memory while it's unplugged, even if you unplug it and don't have any batteries installed. The batteries (see page 9) are just to retain the time of day for the clock if there is a power outage."

Static RAM?

[Knightrider]

I'm pretty sure that mine dumps all timers when the batteries are out and it's unplugged.  My main unit is seldom unhooked from the computer, so I'm only 50% sure of this.

Any time I unhook the cm15a without batteries for an extended period of time, AHP tells me I need to reload the timers and macros.  Maybe this is just a ploy to update the time.

[Brian H]

The CM15A Schematic [yes it can be found on the FCC Equipment Authorization Site and X10 didn't mark it confidential so it is pulblic record]. Shows a 24C64 EEPROM for data storage. It also shows why the 4 AAA Batteries is needed. When on battery; the six volts feeds through a Low Dropout five volt regulator. It powers the chip the does both the Low Speed USB Interface and is also the controller.

[Nate2]

Shows a 24C64 EEPROM for data storage.

Don't EEPROMs have a max # of times you can write to them before they "wear out" ?

[tjosan]

Shows a 24C64 EEPROM for data storage.

Don't EEPROMs have a max # of times you can write to them before they "wear out" ?

Depending on the prefix and price you can find EEproms with 10000, 100000 and 1 million guaranteed write cycles.

[Nate2]

I put in 4 new alkaline batteries into the CM15A (after it was plugged into AC, as the manual suggests on page 9).
Reset battery counter to 48 hours.
Downloaded stuff to CM15A.
Moved CM15A to a different wall outlet (about 3 minutes of no AC power).
Moved CM15A back to computer 2 days later, and AHP reports that my battery counter is zero!

Does removing the AC power start a non-stop countdown of the battery timer?
One would think the timer should pause once you plug it back into AC.

[Nate2]

Does removing the AC power start a non-stop countdown of the battery timer?
One would think the timer should pause once you plug it back into AC.

My mistake.
1 of the batteries was reversed.
Costco (Kirkland) AAA alkaline batteries have a protrusion on the negative terminal as well, so it makes it look like a positive terminal.

Disconnected the CM15a from AC for 8 minutes.
Battery Status (Time Remaining) now indicates 47:50.