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  1. 269 0
      docs/en/modules/ow.md
  2. 2 1
      mkdocs.yml

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docs/en/modules/ow.md

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+# onewire Module
+
+## ow.check_crc16()
+Compute the 1-Wire CRC16 and compare it against the received CRC.
+
+####Syntax
+`ow.check_crc16(buf, inverted_crc0, inverted_crc1[, crc])`
+
+#### Parameters
+  - `buf` string value, data to be calculated check sum in string
+  - `inverted_crc0` LSB of received CRC
+  - `inverted_crc1` MSB of received CRC
+  - `crc` CRC starting value (optional)
+
+#### Returns
+`bool` true, if the CRC matches; false for mismatch.
+
+## ow.crc16()
+Compute a Dallas Semiconductor 16 bit CRC.  This is required to check the integrity of data received from many 1-Wire devices.  Note that the CRC computed here is **not** what you'll get from the 1-Wire network, for two reasons:
+
+1. The CRC is transmitted bitwise inverted.
+2. Depending on the endian-ness of your processor, the binary representation of the two-byte return value may have a different byte order than the two bytes you get from 1-Wire.
+
+#### Syntax
+`ow.crc16(buf[, crc])`
+
+#### Parameters
+  - `buf` string value, data to be calculated check sum in string.
+  - `crc` CRC starting value (optional)
+
+#### Returns
+`crc16` the CRC16, as defined by Dallas Semiconductor.
+
+## ow.crc8()
+Compute a Dallas Semiconductor 8 bit CRC, these are used in the ROM and scratchpad registers.
+
+#### Syntax
+`ow.crc8(buf)`
+
+#### Parameters
+`buf` string value, data to be calculated check sum in string.
+
+#### Returns
+CRC result as byte.
+
+## ow.depower()
+Stop forcing power onto the bus. You only need to do this if you used the 'power' flag to `ow.write()` or used a `ow.write_bytes()` and aren't about to do another read or write.
+
+#### Syntax
+`ow.depower(pin)`
+
+#### Parameters
+`pin` 1~12, IO index
+
+#### Returns
+`nil`
+
+####See also
+  - [ow.write()](#owwrite)
+  - [ow.write_bytes()](#owwrite_bytes)
+
+## ow.read()
+Read a byte.
+
+####Syntax
+`ow.read(pin)`
+
+#### Parameters
+`pin` 1~12, IO index
+
+#### Returns
+Byte read from slave device.
+
+## ow.read_bytes()
+Read multi bytes.
+
+#### Syntax
+`ow.read_bytes(pin, size)`
+
+#### Parameters
+  - `pin` 1~12, IO index
+  - `size` number of bytes to be read from slave device
+
+#### Returns
+`string` bytes read from slave device
+
+## ow.reset_search()
+Clear the search state so that it will start from the beginning again.
+
+#### Syntax
+`ow.reset_search(pin)`
+
+#### Parameters
+`pin` 1~12, IO index
+
+#### Returns
+`nil`
+
+## ow.search()
+Look for the next device.
+
+#### Syntax
+`ow.search(pin)`
+
+#### Parameters
+`pin` 1~12, IO index
+
+#### Returns
+`rom_code` string with length of 8 upon success. It contains the rom code of slave device. Returns `nil` if search was unsuccessful.
+
+#### See also
+[ow.target_search()](#owtargetsearch)
+
+## ow.select()
+Issue a 1-Wire rom select command, make sure you do the `ow.reset(pin)` first.
+
+#### Syntax
+`ow.select(pin, rom)`
+
+#### Parameters
+  - `pin` 1~12, IO index
+  - `rom` string value, len 8, rom code of the salve device
+
+#### Returns
+`nil`
+
+#### Example
+```lua
+-- 18b20 Example
+pin = 9
+ow.setup(pin)
+count = 0
+repeat
+  count = count + 1
+  addr = ow.reset_search(pin)
+  addr = ow.search(pin)
+  tmr.wdclr()
+until (addr ~= nil) or (count > 100)
+if addr == nil then
+  print("No more addresses.")
+else
+  print(addr:byte(1,8))
+  crc = ow.crc8(string.sub(addr,1,7))
+  if crc == addr:byte(8) then
+    if (addr:byte(1) == 0x10) or (addr:byte(1) == 0x28) then
+      print("Device is a DS18S20 family device.")
+        repeat
+          ow.reset(pin)
+          ow.select(pin, addr)
+          ow.write(pin, 0x44, 1)
+          tmr.delay(1000000)
+          present = ow.reset(pin)
+          ow.select(pin, addr)
+          ow.write(pin,0xBE,1)
+          print("P="..present)  
+          data = nil
+          data = string.char(ow.read(pin))
+          for i = 1, 8 do
+            data = data .. string.char(ow.read(pin))
+          end
+          print(data:byte(1,9))
+          crc = ow.crc8(string.sub(data,1,8))
+          print("CRC="..crc)
+          if crc == data:byte(9) then
+             t = (data:byte(1) + data:byte(2) * 256) * 625
+             t1 = t / 10000
+             t2 = t % 10000
+             print("Temperature="..t1.."."..t2.."Centigrade")
+          end                   
+          tmr.wdclr()
+        until false
+    else
+      print("Device family is not recognized.")
+    end
+  else
+    print("CRC is not valid!")
+  end
+end
+```
+
+####See also
+[ow.reset()](#owreset)
+
+## ow.setup()
+Set a pin in onewire mode.
+
+#### Syntax
+`ow.setup(pin)`
+
+#### Parameters
+`pin` 1~12, IO index
+
+#### Returns
+`nil`
+
+## ow.reset()
+Perform a 1-Wire reset cycle.
+
+#### Syntax
+`ow.reset(pin)`
+
+#### Parameters
+`pin` 1~12, IO index
+
+#### Returns
+  - `1` if a device responds with a presence pulse.
+  - `0` if there is no device or the bus is shorted or otherwise held low for more than 250 µS.
+
+## ow.skip()
+Issue a 1-Wire rom skip command, to address all on bus.
+
+#### Syntax
+`ow.skip(pin)`
+
+#### Parameters
+`pin` 1~12, IO index
+
+#### Returns
+`nil`
+
+## ow.target_search()
+Set up the search to find the device type `family_code` on the next call to `ow.search()` if it is present.
+
+#### Syntax
+`ow.target_search(pin, family_code)`
+
+#### Parameters
+  - `pin` 1~12, IO index
+  - `family_code` byte for family code
+
+#### Returns
+`nil`
+
+####See also
+[ow.search()](#owsearch)
+
+## ow.write()
+Write a byte. If `power` is 1 then the wire is held high at the end for parasitically powered devices. You are responsible for eventually depowering it by calling `ow.depower()` or doing another read or write.
+
+#### Syntax
+`ow.write(pin, v, power)`
+
+#### Parameters
+  - `pin` 1~12, IO index
+  - `v` byte to be written to salve device 
+  - `power` 1 for wire being held high for parasitically powered devices
+
+#### Returns
+`nil`
+
+####See also
+[ow.depower()](#owdepower)
+
+## ow.write_bytes()
+Write multi bytes. If `power` is 1 then the wire is held high at the end for parasitically powered devices. You are responsible for eventually depowering it by calling `ow.depower()` or doing another read or write.
+
+#### Syntax
+`ow.write_bytes(pin, buf, power)`
+
+#### Parameters
+  - `pin` 1~12, IO index
+  - `buf` string to be written to slave device
+  - `power` 1 for wire being held high for parasitically powered devices
+
+#### Returns
+`nil`
+
+####See also
+[ow.depower()](#owdepower)

+ 2 - 1
mkdocs.yml

@@ -43,9 +43,10 @@ pages:
         - 'http': 'en/modules/http.md'
         - 'hx711' : 'en/modules/hx711.md'
         - 'i2c' : 'en/modules/i2c.md'
+        - 'mqtt': 'en/modules/mqtt.md'
         - 'net': 'en/modules/net.md'
         - 'node': 'en/modules/node.md'
-        - 'mqtt': 'en/modules/mqtt.md'
+        - 'ow': 'en/modules/ow.md'
         - 'pwm' : 'en/modules/pwm.md'
         - 'rtcmem': 'en/modules/rtcmem.md'
         - 'rtctime': 'en/modules/rtctime.md'