Changeset 2544

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Timestamp:
05/17/04 20:37:12 (9 years ago)
Author:
khali
Message:

The driver now supports thermistor inputs (PC87366). Update

fan clock divisor info.

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1 modified

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  • lm-sensors/trunk/doc/chips/pc87360

    r2508 r2544  
    22========================= 
    33 
    4 Status: Beta, somewhat tested. 
     4Status: Beta, PC87366 well tested, other chips untested. 
    55 
    66Supported chips: 
     
    1717 
    1818Thanks to Sandeep Mehta, Tonko de Rooy and Daniel Ceregatti for testing. 
     19Thanks to Rudolf Marek for helping me investigate conversion issues. 
    1920 
    2021 
     
    4243(PC87366) remote temperatures. 
    4344 
     45The driver assumes that no more than one chip is present, and the standard 
     46Super I/O address is used (0x2E/0x2F). 
     47 
    4448 
    4549Fan Monitoring 
     
    5256divider) in this case. 
    5357 
    54 Fan readings are affected by a programmable clock divider (1, 2, 4 or 8). 
    55 By changing the divider, you give the readings more range or accuracy. 
     58Fan readings are affected by a programmable clock divider, giving the 
     59readings more range or accuracy. Usually, users have to learn how it works, 
     60but this driver implements dynamic clock divider selection, so you don't 
     61have to care no more. 
     62 
     63For reference, here are a few values about clock dividers: 
    5664 
    5765                slowest         accuracy        highest 
     
    7078RPM as the lowest acceptable accuracy. 
    7179 
    72 Note that not all RPM values can be represented. This is not only true for 
    73 the measured speeds, but also for the programmable low limits, so don't be 
    74 surprised if you try to set, say, fan1_min to 2900 and it finaly reads 
    75 2909. Likewise, if you try to set fan1_min to 0, it'll be set to the 
    76 lowest representable RPM value (depending on the divider). 
     80As mentioned above, you don't have to care about this no more. 
     81 
     82Note that not all RPM values can be represented, even when the best clock 
     83divider is selected. This is not only true for the measured speeds, but 
     84also for the programmable low limits, so don't be surprised if you try to 
     85set, say, fan1_min to 2900 and it finaly reads 2909. 
    7786 
    7887 
     
    103112 
    104113The PC87366 has three additional temperature channels, based on 
    105 thermistors (as opposed to thermal diodes for the first temperature 
     114thermistors (as opposed to thermal diodes for the first three temperature 
    106115channels). For technical reasons, these channels are held by the VLM 
    107116(voltage level monitor) logical device, not the TMS (temperature 
    108 measurement) one. The formula to convert the measured voltage into a 
    109 temperature isn't known, so the driver doesn't handle these temperature 
    110 channels at all yet. 
     117measurement) one. As a consequence, these temperatures are exported as 
     118voltages, and converted into temperatures in user-space. 
    111119 
    112120 
     
    122130sensors.conf accordingly. National Semiconductor has a document with 
    123131recommended resistor values for some voltages, but this still leaves much 
    124 room for per motherboard specificities, unfortunately. 
     132room for per motherboard specificities, unfortunately. Even worse, 
     133motherboard manufacturers don't seem to care about National Semiconductor's 
     134recommendations. 
    125135 
    126136Each voltage measured has associated low and high limit, each of which 
     
    150160----------- 
    151161 
    152 There are a few unimplemented configuration options at the moment. We'll 
    153 add them if someone needs them. 
    154  
    155162The datasheets suggests that some values (fan mins, fan dividers) 
    156163shouldn't be changed once the monitoring has started, but we ignore that