w1_ds28e04.rst 1.3 KB

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  1. ========================
  2. Kernel driver w1_ds28e04
  3. ========================
  4. Supported chips:
  5. * Maxim DS28E04-100 4096-Bit Addressable 1-Wire EEPROM with PIO
  6. supported family codes:
  7. ================= ====
  8. W1_FAMILY_DS28E04 0x1C
  9. ================= ====
  10. Author: Markus Franke, <[email protected]> <[email protected]>
  11. Description
  12. -----------
  13. Support is provided through the sysfs files "eeprom" and "pio". CRC checking
  14. during memory accesses can optionally be enabled/disabled via the device
  15. attribute "crccheck". The strong pull-up can optionally be enabled/disabled
  16. via the module parameter "w1_strong_pullup".
  17. Memory Access
  18. A read operation on the "eeprom" file reads the given amount of bytes
  19. from the EEPROM of the DS28E04.
  20. A write operation on the "eeprom" file writes the given byte sequence
  21. to the EEPROM of the DS28E04. If CRC checking mode is enabled only
  22. fully aligned blocks of 32 bytes with valid CRC16 values (in bytes 30
  23. and 31) are allowed to be written.
  24. PIO Access
  25. The 2 PIOs of the DS28E04-100 are accessible via the "pio" sysfs file.
  26. The current status of the PIO's is returned as an 8 bit value. Bit 0/1
  27. represent the state of PIO_0/PIO_1. Bits 2..7 do not care. The PIO's are
  28. driven low-active, i.e. the driver delivers/expects low-active values.