Changeset 2508

2004-05-08 12:15:57 (11 years ago)


1 modified


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

    r2480 r2508  
    4 Status: Alpha, untested. 
     4Status: Beta, somewhat tested. 
    66Supported chips: 
    1616Authors: Jean Delvare <> 
     18Thanks to Sandeep Mehta, Tonko de Rooy and Daniel Ceregatti for testing. 
    1921Module Parameters 
    22 None. 
     24init (int): 
     25  Chip initialization level: 
     26   0: None 
     27  *1: Forcibly enable internal voltage and temperature channels, except in9 
     28   2: Forcibly enable all voltage and temperature channels, except in9 
     29   3: Forcibly enable all voltage and temperature channels, including in9 
    3239The National Semiconductor PC87365 and PC87366 Super I/O chips are complete 
    3340hardware monitoring chipsets, not only controling and monitoring three fans, 
    34 but also monitoring eleven voltage inputs and two (PC87365) or three 
     41but also monitoring eleven voltage inputs and two (PC87365) or six 
    3542(PC87366) remote temperatures. 
     45Fan Monitoring 
    3748Fan rotation speeds are reported in RPM (revolutions per minute). An alarm 
    3849is triggered if the rotation speed has dropped below a programmable limit. 
    39 Fan readings can be divided by a programmable divider (1, 2, 4 or 8) to give 
    40 the readings more range or accuracy. Not all RPM values can accurately be 
    41 represented, so some rounding is done. With a divider of 2, the lowest 
    42 representable value is around 950 RPM. See doc/fan-divisors for details. 
     50A different alarm is triggered if the fan speed is too low to be measured. 
     51It is suggested to increase the fan divider (which is really a clock 
     52divider) in this case. 
    44 A different alarm is also triggered if the fan speed is too low to be 
    45 measured. It is suggested to increase the fan divisor in this case. 
     54Fan readings are affected by a programmable clock divider (1, 2, 4 or 8). 
     55By changing the divider, you give the readings more range or accuracy. 
    47 PWM values are from 0 to 255. 
     57                slowest         accuracy        highest 
     58                measurable      around 3000     accurate 
     59    divider     speed (RPM)     RPM (RPM)       speed (RPM) 
     60         1        1882              18           6928 
     61         2         941              37           4898 
     62         4         470              74           3464 
     63         8         235             150           2449 
     65For the curious, here is how the values above were computed: 
     66 * slowest measurable speed: clock/(255*divider) 
     67 * accuracy around 3000 RPM: 3000^2/clock 
     68 * highest accurate speed: sqrt(clock*100) 
     69The clock speed for the PC87360 family is 480 kHz. I arbitrarily chose 100 
     70RPM as the lowest acceptable accuracy. 
     72Note that not all RPM values can be represented. This is not only true for 
     73the measured speeds, but also for the programmable low limits, so don't be 
     74surprised if you try to set, say, fan1_min to 2900 and it finaly reads 
     752909. Likewise, if you try to set fan1_min to 0, it'll be set to the 
     76lowest representable RPM value (depending on the divider). 
     79Fan Control 
     82PWM (pulse width modulation) values range from 0 to 255, with 0 meaning 
     83that the fan is stopped, and 255 meaning that the fan goes at full speed. 
     85Be extremely careful when changing PWM values. Low PWM values, even 
     86non-zero, can stop the fan, which may cause irreversible damage to your 
     87hardware if temperature increases too much. When changing PWM values, go 
     88step by step and keep an eye on temperatures. 
     90One user reported problems with PWM. Changing PWM values would break fan 
     91speed readings. No explanation nor fix could be found. 
     94Temperature Monitoring 
    4997Temperatures are reported in degrees Celcius. Each temperature measured has 
    50 associated low, limit and overtemperature limits, each of which triggers an 
     98associated low, high and overtemperature limits, each of which triggers an 
    5199alarm when crossed. 
    54102only) is internal. 
     104The PC87366 has three additional temperature channels, based on 
     105thermistors (as opposed to thermal diodes for the first temperature 
     106channels). For technical reasons, these channels are held by the VLM 
     107(voltage level monitor) logical device, not the TMS (temperature 
     108measurement) one. The formula to convert the measured voltage into a 
     109temperature isn't known, so the driver doesn't handle these temperature 
     110channels at all yet. 
     113Voltage Monitoring 
    56116Voltages are reported relatively to a reference voltage, either internal or 
    57 external. Some of them are divided by two internally, you will have to 
    58 compensate in sensors.conf. Each voltage measured has associated low and 
    59 high limit, each of which triggers an alarm when crossed. 
     117external. Some of them (in7:Vsb, in8:Vdd and in10:AVdd) are divided by two 
     118internally, you will have to compensate in sensors.conf. Others (in0 to in6) 
     119are likely to be divided externally. The meaning of each of these inputs as 
     120well as the values of the resistors used for division is left to the 
     121motherboard manufacturers, so you will have to document yourself and edit 
     122sensors.conf accordingly. National Semiconductor has a document with 
     123recommended resistor values for some voltages, but this still leaves much 
     124room for per motherboard specificities, unfortunately. 
     126Each voltage measured has associated low and high limit, each of which 
     127triggers an alarm when crossed. 
     130General Remarks 
    61133If an alarm triggers, it will remain triggered until the hardware register 
    62 is read at least once. This means that the cause for the alarm may  
    63 already have disappeared!  Note that in the current implementation, all 
    64 hardware registers are read whenever any data is read (unless it is less 
    65 than 1.5 seconds since the last update). This means that you can easily 
    66 miss once-only alarms. 
     134is read at least once. This means that the cause for the alarm may already 
     135have disappeared! Note that all hardware registers are read whenever any 
     136data is read (unless it is less than 2 seconds since the last update, in 
     137which case cached values are returned instead). As a consequence, when 
     138a once-only alarm triggers, it may take 2 seconds for it to show, and 2 
     139more seconds for it to disappear. 
     141Monitoring of in9 isn't enabled at lower init levels (<3) because that 
     142channel measures the battery voltage (Vbat). It is a known fact that 
     143repeatedly sampling the battery voltage reduces its lifetime. National 
     144Semiconductor smartly designed their chipset so that in9 is sampled only 
     145once every 1024 sampling cycles (that is every 34 minutes at the default 
     146sampling rate), so the effect is attenuated, but still present. 
    73153add them if someone needs them. 
    75 The datasheets suggests that some values (fan mins, fan divisors) 
     155The datasheets suggests that some values (fan mins, fan dividers) 
    76156shouldn't be changed once the monitoring has started, but we ignore that 
    77157recommendation. We'll reconsider if it actually causes trouble.