sht15.rst 2.3 KB

1234567891011121314151617181920212223242526272829303132333435363738394041424344454647484950515253545556575859606162636465666768697071727374757677787980818283
  1. Kernel driver sht15
  2. ===================
  3. Authors:
  4. * Wouter Horre
  5. * Jonathan Cameron
  6. * Vivien Didelot <[email protected]>
  7. * Jerome Oufella <[email protected]>
  8. Supported chips:
  9. * Sensirion SHT10
  10. Prefix: 'sht10'
  11. * Sensirion SHT11
  12. Prefix: 'sht11'
  13. * Sensirion SHT15
  14. Prefix: 'sht15'
  15. * Sensirion SHT71
  16. Prefix: 'sht71'
  17. * Sensirion SHT75
  18. Prefix: 'sht75'
  19. Datasheet: Publicly available at the Sensirion website
  20. http://www.sensirion.ch/en/pdf/product_information/Datasheet-humidity-sensor-SHT1x.pdf
  21. Description
  22. -----------
  23. The SHT10, SHT11, SHT15, SHT71, and SHT75 are humidity and temperature
  24. sensors.
  25. The devices communicate using two GPIO lines.
  26. Supported resolutions for the measurements are 14 bits for temperature and 12
  27. bits for humidity, or 12 bits for temperature and 8 bits for humidity.
  28. The humidity calibration coefficients are programmed into an OTP memory on the
  29. chip. These coefficients are used to internally calibrate the signals from the
  30. sensors. Disabling the reload of those coefficients allows saving 10ms for each
  31. measurement and decrease power consumption, while losing on precision.
  32. Some options may be set via sysfs attributes.
  33. Notes:
  34. * The regulator supply name is set to "vcc".
  35. * If a CRC validation fails, a soft reset command is sent, which resets
  36. status register to its hardware default value, but the driver will try to
  37. restore the previous device configuration.
  38. Platform data
  39. -------------
  40. * checksum:
  41. set it to true to enable CRC validation of the readings (default to false).
  42. * no_otp_reload:
  43. flag to indicate not to reload from OTP (default to false).
  44. * low_resolution:
  45. flag to indicate the temp/humidity resolution to use (default to false).
  46. Sysfs interface
  47. ---------------
  48. ================== ==========================================================
  49. temp1_input temperature input
  50. humidity1_input humidity input
  51. heater_enable write 1 in this attribute to enable the on-chip heater,
  52. 0 to disable it. Be careful not to enable the heater
  53. for too long.
  54. temp1_fault if 1, this means that the voltage is low (below 2.47V) and
  55. measurement may be invalid.
  56. humidity1_fault same as temp1_fault.
  57. ================== ==========================================================