Editing Mer/Documentation/BME Protocol
Warning: You are not logged in.
Your IP address will be recorded in this page's edit history.
The edit can be undone.
Please check the comparison below to verify that this is what you want to do, and then save the changes below to finish undoing the edit.
Latest revision | Your text | ||
Line 1: | Line 1: | ||
- | + | This documentation is entirely for the purpose of implementing software gathering battery information on Nokia Internet Tablets, not alteration of battery management state. | |
- | + | ||
- | This documentation is entirely for the purpose of implementing software gathering battery information on Nokia Internet Tablets, not alteration of battery management state | + | |
- | + | ||
- | + | ||
- | + | ||
- | + | ||
Existing code: | Existing code: | ||
Line 99: | Line 93: | ||
</pre> | </pre> | ||
- | The '''“Instantaneous battery voltage (mV)”''' field’s observed values have a certain regular spacing indicating a linear function of some integer value with a smaller range, presumably retu adc register #8. If it is indeed from that register, then note there is a non-zero offset involved: one function that gives values consistent with the set of values observed and that somewhat matches one set of observations of both fields (which unfortunately had a non-negligible delay between sampling the two) is mV = 2252.362 + 2.81361 * adc#8 (where the multiplier is fairly accurate, | + | The '''“Instantaneous battery voltage (mV)”''' field’s observed values have a certain regular spacing indicating a linear function of some integer value with a smaller range, presumably retu adc register #8. If it is indeed from that register, then note there is a non-zero offset involved: one function that gives values consistent with the set of values observed and that somewhat matches one set of observations of both fields (which unfortunately had a non-negligible delay between sampling the two) is mV = 2252.362 + 2.81361 * adc#8 (where the multiplier is fairly accurate, but the constant could be out by some multiple of 2.81361). -- pjrm. |
- | + | ||
- | + | ||
- | + | ||
- | + | ||
- | The '''“Battery monitor check voltage (mV)”''' field has similar values to the “Instantaneous battery voltage (mV)” field, but without obvious regular spacing. I | + | The '''“Battery monitor check voltage (mV)”''' field has similar values to the “Instantaneous battery voltage (mV)” field, but without obvious regular spacing. I don't know how it's calculated. -- pjrm. |
Voltage levels depend not just on amount of charge remaining in the battery, but also recent electrical load: the voltage level goes down markedly while the CPU is being heavily used, for example. | Voltage levels depend not just on amount of charge remaining in the battery, but also recent electrical load: the voltage level goes down markedly while the CPU is being heavily used, for example. |
Learn more about Contributing to the wiki.