linux/Documentation/hwmon/adc128d818
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   1Kernel driver adc128d818
   2========================
   3
   4Supported chips:
   5  * Texas Instruments ADC818D818
   6    Prefix: 'adc818d818'
   7    Addresses scanned: I2C 0x1d, 0x1e, 0x1f, 0x2d, 0x2e, 0x2f
   8    Datasheet: Publicly available at the TI website
   9               http://www.ti.com/
  10
  11Author: Guenter Roeck
  12
  13Description
  14-----------
  15
  16This driver implements support for the Texas Instruments ADC128D818.
  17It is described as 'ADC System Monitor with Temperature Sensor'.
  18
  19The ADC128D818 implements one temperature sensor and seven voltage sensors.
  20
  21Temperatures are measured in degrees Celsius. There is one set of limits.
  22When the HOT Temperature Limit is crossed, this will cause an alarm that will
  23be reasserted until the temperature drops below the HOT Hysteresis.
  24Measurements are guaranteed between -55 and +125 degrees. The temperature
  25measurement has a resolution of 0.5 degrees; the limits have a resolution
  26of 1 degree.
  27
  28Voltage sensors (also known as IN sensors) report their values in volts.
  29An alarm is triggered if the voltage has crossed a programmable minimum
  30or maximum limit. Note that minimum in this case always means 'closest to
  31zero'; this is important for negative voltage measurements. All voltage
  32inputs can measure voltages between 0 and 2.55 volts, with a resolution
  33of 0.625 mV.
  34
  35If an alarm triggers, it will remain triggered until the hardware register
  36is read at least once. This means that the cause for the alarm may
  37already have disappeared by the time the alarm is read. The driver
  38caches the alarm status for each sensor until it is at least reported
  39once, to ensure that alarms are reported to user space.
  40
  41The ADC128D818 only updates its values approximately once per second;
  42reading it more often will do no harm, but will return 'old' values.
  43
  44In addition to the scanned address list, the chip can also be configured for
  45addresses 0x35 to 0x37. Those addresses are not scanned. You have to instantiate
  46the driver explicitly if the chip is configured for any of those addresses in
  47your system.
  48