Datasheet

3.2 So, how does it work, then?
During power-up (boot sequence) or after a reset
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, the console performs internal checks
and determines whether a data logger is connected.
For non-green dot consoles upgraded to firmware version ≥ 3.12, the serial line and
data logging functions remain available. Users remain free to utilize their third-party
data loggers, old-school Davis data loggers, direct serial line communication, etc.
The new green dot consoles, however, start out on an authentication scheme to en-
sure that the attached data logger constitutes an original piece of Davis equipment. If
the authentication fails, the console will display the ”INCOMPATIBLE LOGGER” mes-
sage until it is powered down again.
Figure 6: Firmware version ≥ 3.12 data logger authentication. The authentication only takes place
if the console itself is identified as a green dot console. Firmware version 3.00 has only been shipped
preinstalled on new consoles, whereas version 3.12 can be downloaded to upgrade existing consoles. The
”not applicable” branch is followed when the data logger does not return a valid status code.
3.3 Demystifying the authentication process
A qualified attempt at outlining the authentication process can be made by:
• Assuming that no extra hardware has been added to the data logger. To keep unit
cost at a minimum, Davis equipment does not utilize top-notch environmental
sensors. In line with this, assuming that no extra hardware (such as an Atmel
CryptoMemory chip) has been added to the data logger, as it would increase unit
cost — seems like a good place to start.
• Comparing the components found inside the green dot and the non-green dot data
loggers verifies that the above assumption is correct.
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By grounding pin 7 (reset) of the expansion connector.
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