|SPD Self Test|
Message #5 Posted by Andrés C. Rodríguez (Argentina) on 13 Oct 2002, 5:16 p.m.,
in response to message #4 by Christof (Davis, CA)
I was always puzzled by the SPD XXXXX output of the self tests, the value varies slightly from trial to trial, and only some values are possible (I mean frequently observed). SPD may mean Speed (?), I noticed the 48G+ brings a value almost 4 times as high as the 42. I was unable to firmly correlate the SPD values with battery charge status.
Supposing it is kind of a timer or counter related to CPU clock or instruction execution speed, I wonder *what* could be the reference for such measurement, since the 42S has no quartz crystal to measure against.... May it be a strange case of self-reference?
In my 42S, usual values are in the form 104XXXX, the values of XXXX are 6624, 7200, 7776, 8352, 8928, 9504; 7776, 8352 and 8928 are most frequent. It seems that the "quantum" in this scale is 576, which is 512+64 ...
In the 48G+, for values in the form 36XXXXX, some values for XXXXX are 83056, 83472, 85216, 86080, 86960, 87824, 88704, 89568, 90448, 91312, 93936. It seems to vary more than in the 42S, and there is not a clear step, the smallest one I saw is 416, but most are either 864 or 880.