device data to its embedded EEPROM, either restore data
embedded in device EEPROM. Be aware that devices support
limited EEPROM writing cycles (typical 50k)
+
* 'save': save device RAM to EEPROM
* 'restore': restore EEPROM data in device RAM
+
Users: any user space application which wants to communicate with
w1_term device
Contact: Akira Shimahara <akira215corp@gmail.com>
Description:
(RO) return the power status by asking the device
+
* '0': device parasite powered
* '1': device externally powered
* '-xx': xx is kernel error when reading power status
+
Users: any user space application which wants to communicate with
w1_term device
will be changed only in device RAM, so it will be cleared when
power is lost. Trigger a 'save' to EEPROM command to keep
values after power-on. Read or write are :
+
* '9..14': device resolution in bit
- or resolution to set in bit
+ or resolution to set in bit
* '-xx': xx is kernel error when reading the resolution
* Anything else: do nothing
+
Some DS18B20 clones are fixed in 12-bit resolution, so the
actual resolution is read back from the chip and verified. Error
is reported if the results differ.
Contact: Akira Shimahara <akira215corp@gmail.com>
Description:
(RO) return the temperature in 1/1000 degC.
+
* If a bulk read has been triggered, it will directly
- return the temperature computed when the bulk read
- occurred, if available. If not yet available, nothing
- is returned (a debug kernel message is sent), you
- should retry later on.
+ return the temperature computed when the bulk read
+ occurred, if available. If not yet available, nothing
+ is returned (a debug kernel message is sent), you
+ should retry later on.
* If no bulk read has been triggered, it will trigger
- a conversion and send the result. Note that the
- conversion duration depend on the resolution (if
- device support this feature). It takes 94ms in 9bits
- resolution, 750ms for 12bits.
+ a conversion and send the result. Note that the
+ conversion duration depend on the resolution (if
+ device support this feature). It takes 94ms in 9bits
+ resolution, 750ms for 12bits.
+
Users: any user space application which wants to communicate with
w1_term device
(RW) return the temperature in 1/1000 degC.
*read*: return 2 lines with the hexa output data sent on the
bus, return the CRC check and temperature in 1/1000 degC
- *write* :
+ *write*:
+
* '0' : save the 2 or 3 bytes to the device EEPROM
- (i.e. TH, TL and config register)
+ (i.e. TH, TL and config register)
* '9..14' : set the device resolution in RAM
- (if supported)
+ (if supported)
* Anything else: do nothing
+
refer to Documentation/w1/slaves/w1_therm.rst for detailed
information.
Users: any user space application which wants to communicate with
Contact: Akira Shimahara <akira215corp@gmail.com>
Description:
(RW) trigger a bulk read conversion. read the status
+
*read*:
- * '-1': conversion in progress on at least 1 sensor
- * '1' : conversion complete but at least one sensor
+ * '-1':
+ conversion in progress on at least 1 sensor
+ * '1' :
+ conversion complete but at least one sensor
value has not been read yet
- * '0' : no bulk operation. Reading temperature will
+ * '0' :
+ no bulk operation. Reading temperature will
trigger a conversion on each device
- *write*: 'trigger': trigger a bulk read on all supporting
+
+ *write*:
+ 'trigger': trigger a bulk read on all supporting
devices on the bus
+
Note that if a bulk read is sent but one sensor is not read
immediately, the next access to temperature on this device
will return the temperature measured at the time of issue
reset to default (datasheet) conversion time for a new
resolution.
- *read*: Actual conversion time in milliseconds. *write*:
- '0': Set the default conversion time from the datasheet.
- '1': Measure and set the conversion time. Make a single
+ *read*:
+ Actual conversion time in milliseconds.
+
+ *write*:
+ * '0':
+ Set the default conversion time from the datasheet.
+ * '1':
+ Measure and set the conversion time. Make a single
temperature conversion, measure an actual value.
Increase it by 20% for temperature range. A new
conversion time can be obtained by reading this
same attribute.
- other positive value:
+ * other positive value:
Set the conversion time in milliseconds.
Users: An application using the w1_term device
(RW) Control optional driver settings.
Bit masks to read/write (bitwise OR):
- 1: Enable check for conversion success. If byte 6 of
+ == ============================================================
+ 1 Enable check for conversion success. If byte 6 of
scratchpad memory is 0xC after conversion, and
temperature reads 85.00 (powerup value) or 127.94
(insufficient power) - return a conversion error.
- 2: Enable poll for conversion completion. Generate read cycles
+ 2 Enable poll for conversion completion. Generate read cycles
after the conversion start and wait for 1's. In parasite
power mode this feature is not available.
+ == ============================================================
+
+ *read*:
+ Currently selected features.
- *read*: Currently selected features.
- *write*: Select features.
+ *write*:
+ Select features.
Users: An application using the w1_term device
projects / linux-2.6-microblaze.git / blobdiff