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       DS2450 - Quad A/D Converter


   Voltage * 4 and Memory.
       20 [.]XXXXXXXXXXXX[XX][/[ PIO.[A-D|ALL] | volt.[A-D|ALL] | volt2.[A-D|ALL] ]]

       20 [.]XXXXXXXXXXXX[XX][/[ 8bit/volt.[A-D|ALL] | 8bit/volt2.[A-D|ALL] ]]

       20 [.]XXXXXXXXXXXX[XX][/[ memory | pages/page.[0-3|ALL] | power ]

       20  [.]XXXXXXXXXXXX[XX][/[ alarm/high.[A-D|ALL] | alarm/low.[A-D|ALL] | set_alarm/high.[A-
       D|ALL]  |  set_alarm/low.[A-D|ALL]  |  set_alarm/unset  |  set_alarm/volthigh.[A-D|ALL]  |
       set_alarm/volt2high.[A-D|ALL] | set_alarm/voltlow.[A-D|ALL] | set_alarm/volt2low.[A-D|ALL]

       20 [.]XXXXXXXXXXXX[XX][/[ address | crc8 | id | locator | r_address | r_id |  r_locator  |
       type ]]

   CO2 sensor
       20 [.]XXXXXXXXXXXX[XX][/[ CO2/ppm | CO2/power | CO2/status ]




   alarm/high.A ... alarm/high.D alarm.high.ALL
   alarm/high.A ... alarm/high.D alarm.high.ALL
       read-write, binary
       The alarm state of the voltage channel. The alarm state is set one of two ways:

       voltage conversion
              Whenever  the  DS2450  measures a voltage on a channel, that voltage is compared to
              the high and low limits set_alarm/volthigh  and/or  set_alarm/voltlow  and  if  the
              alarm  is enabled set_alarm/high and/or set_alarm/low the corresponding flag is set
              in alarm/high and/or alarm/low

       manual set
              The flag can be set by a direct write to alarm/high or alarm/low

       read-write, binary
       32 bytes of data. Much has special implications. See the datasheet.

   pages/page.0 ... pages/page.3 pages/page.ALL
       read-write, binary
       Memory is split into 4 pages of 8 bytes  each.  Mostly  for  reading  and  setting  device
       properties. See the datasheet for details.
       ALL is an aggregate of the pages. Each page is accessed sequentially.

       read-write, yes-no
       Pins  used for digital control. 1 turns the switch on (conducting). 0 turns the switch off
       Control is specifically enabled. Reading volt will turn off this control.
       ALL is an aggregate of the voltages. Readings are made separately.

       read-write, yes-no
       Is the DS2450 externally powered? (As opposed  to  parasitically  powered  from  the  data
       The  analog  A/D   will  be  kept  on  continuously. And the bus will be released during a
       conversion allowing other devices to communicate.
       Set true (1) only if Vcc powered (not parasitically powered).  Unfortunately,  the  DS2450
       cannot  sense  it's  powered  state.  This  flag must be explicitly written, and thus is a
       potential source of error if incorrectly set.
       It is always safe to leave power set to the default 0 (off) state.

   set_alarm/high.A ... set_alarm/high.D set_alarm/high.ALL
   set_alarm/low.A ... set_alarm/low.D set_alarm/low.ALL
       read-write, yes-no
       Enabled status of the voltage threshold. 1 is on. 0 is off.

   set_alarm/volthigh.A ... set_alarm/volthigh.D set_alarm/volthigh.ALL
   set_alarm/volt2high.A ... set_alarm/volt2high.D set_alarm/volt2high.ALL
   set_alarm/voltlow.A ... set_alarm/voltlow.D set_alarm/voltlow.ALL
   set_alarm/volt2low.A ... set_alarm/volt2low.D set_alarm/volt2low.ALL
       read-write, floating point
       The upper or lower limit for the voltage measured before triggering an alarm.
       Note that the alarm must be enabled alarm/high or alarm.low and an actual reading must  be
       requested  volt  for  the alarm state to actually be set. The alarm state can be sensed at
       alarm/high and alarm/low

       read-write, yes-no
       Status of the power-on-reset (POR) flag.
       The POR is set when the DS2450 is first powered up, and will match the alarm  state  until
       explicitly cleared. (By writing 0 to it).
       The  purpose  of  the  POR is to alert the user that the chip is not yet fully configured,
       especially alarm thresholds and enabling.

   volt.A ... volt.D volt.ALL
   8bit/volt.A ... 8bit/volt.D 8bit/volt.ALL
       read-only, floating point
       Voltage read, 16 bit resolution (or 8 bit for the 8bit directory). Range 0 - 5.10V.
       Output ( PIO ) is specifically disabled.
       ALL is an aggregate of the voltages. Readings are made separately.

   volt2.A ... volt2.D volt2.ALL
   8bit/volt2.A ... 8bit/volt2.D 8bit/volt2.ALL
       read-only, floating point
       Voltage read, 16 bit resolution (or 8 bit for the 8bit directory). Range 0 - 2.55V.
       Output ( PIO ) is specifically disabled.
       ALL is an aggregate of the voltages. Readings are made separately.


       The CO2 sensor is a device constructed from a SenseAir K30 and a DS2450

       read-only, floating point
       Supply voltage to the CO2 sensor (should be around 5V)

       read-only, unsigned
       CO2 level in ppm (parts per million). Range 0-5000.

       read-only, yes-no
       Is the internal voltage correct (around 3.2V)?


       read-only, ascii
       The entire 64-bit unique ID. Given as upper case hexidecimal digits (0-9A-F).
       address starts with the family code
       r address is the address in reverse order, which is often used in other  applications  and

       read-only, ascii
       The  8-bit  error  correction  portion.  Uses  cyclic  redundancy check. Computed from the
       preceding 56 bits of the unique ID number. Given as upper case hexidecimal  digits  (0-9A-

       read-only, ascii
       The  8-bit  family  code.  Unique  to each type of device. Given as upper case hexidecimal
       digits (0-9A-F).

       read-only, ascii
       The 48-bit middle portion of the unique ID number. Does not include  the  family  code  or
       CRC. Given as upper case hexidecimal digits (0-9A-F).
       r id is the id in reverse order, which is often used in other applications and labeling.

       read-only, ascii
       Uses  an  extension  of  the 1-wire design from iButtonLink company that associated 1-wire
       physical connections with a unique 1-wire code. If the connection is behind a Link Locator
       the  locator  will  show  a  unique 8-byte number (16 character hexidecimal) starting with
       family code FE.
       If no Link Locator is between the device and the master, the locator field will be all FF.
       r locator is the locator in reverse order.

   present (DEPRECATED)
       read-only, yes-no
       Is the device currently present on the 1-wire bus?

       read-only, ascii
       Part name assigned by Dallas Semi. E.g.  DS2401 Alternative packaging  (iButton  vs  chip)
       will not be distiguished.




       1-wire  is  a  wiring  protocol  and series of devices designed and manufactured by Dallas
       Semiconductor, Inc. The bus is a low-power low-speed low-connector scheme where  the  data
       line can also provide power.

       Each  device  is  uniquely  and  unalterably numbered during manufacture. There are a wide
       variety of devices, including memory, sensors (humidity,  temperature,  voltage,  contact,
       current),  switches,  timers  and  data  loggers.  More complex devices (like thermocouple
       sensors) can be built with these basic devices. There are also 1-wire  devices  that  have
       encryption included.

       The  1-wire  scheme uses a single bus master and multiple slaves on the same wire. The bus
       master initiates  all  communication.  The  slaves  can  be  individually  discovered  and
       addressed using their unique ID.

       Bus  masters  come in a variety of configurations including serial, parallel, i2c, network
       or USB adapters.

   OWFS design
       OWFS is a suite of programs that designed to make the 1-wire bus and  its  devices  easily
       accessible.  The underlying priciple is to create a virtual filesystem, with the unique ID
       being the directory, and the individual properties of the device are represented as simple
       files that can be read and written.

       Details of the individual slave or master design are hidden behind a consistent interface.
       The goal is to provide an easy set of tools for a software designer to  create  monitoring
       or  control  applications.  There are some performance enhancements in the implementation,
       including data caching,  parallel  access  to  bus  masters,  and  aggregation  of  device
       communication.  Still  the  fundemental  goal  has  been  ease  of  use,  flexibility  and
       correctness rather than speed.

       The DS2450 (3) is a (supposedly) high resolution A/D converter  with  4  channels.  Actual
       resolutin  is  reporterd to be 8 bits. The channels can also function as switches. Voltage
       sensing (with temperature and current, but sometimes restricted voltrage ranges) can  also
       be obtained with the DS2436 , DS2438 and DS276x


       All  1-wire  devices  are factory assigned a unique 64-bit address. This address is of the

       Family Code
              8 bits

              48 bits

       CRC    8 bits

       Addressing under OWFS is in hexidecimal, of form:


       where 01 is an example 8-bit family code, and 12345678ABC is an example 48 bit address.

       The dot is optional, and the CRC code can included. If included, it must be correct.



       CO2 sensor

       CO2 device


       owfs (1) owhttpd (1) owftpd (1) owserver (1) owdir (1) owread (1)  owwrite  (1)  owpresent
       (1) owtap (1)

   Configuration and testing
       owfs (5) owtap (1) owmon (1)

   Language bindings
       owtcl (3) owperl (3) owcapi (3)

       DS1427 (3) DS1904(3) DS1994 (3) DS2404 (3) DS2404S (3) DS2415 (3) DS2417 (3)

       DS2401 (3) DS2411 (3) DS1990A (3)

       DS1982  (3)  DS1985  (3) DS1986 (3) DS1991 (3) DS1992 (3) DS1993 (3) DS1995 (3) DS1996 (3)
       DS2430A (3) DS2431 (3) DS2433 (3) DS2502 (3) DS2506 (3) DS28E04 (3) DS28EC20 (3)

       DS2405 (3) DS2406 (3) DS2408 (3) DS2409 (3) DS2413 (3) DS28EA00 (3)

       DS1822 (3) DS1825 (3) DS1820 (3) DS18B20 (3) DS18S20 (3) DS1920 (3) DS1921 (3) DS1821  (3)
       DS28EA00  (3)  DS28E04  (3)  EDS0064  (3)  EDS0065 (3) EDS0066 (3) EDS0067 (3) EDS0068 (3)
       EDS0071 (3) EDS0072 (3)

       DS1922 (3) DS2438 (3) EDS0065 (3) EDS0068 (3)

       DS2450 (3)

       DS2890 (3)

   Multifunction (current, voltage, temperature)
       DS2436 (3) DS2437 (3) DS2438 (3) DS2751 (3) DS2755 (3) DS2756 (3) DS2760  (3)  DS2770  (3)
       DS2780 (3) DS2781 (3) DS2788 (3) DS2784 (3)

       DS2423 (3)

   LCD Screen
       LCD (3) DS2408 (3)

       DS1977 (3)

       DS2406 (3) -- TAI8570 EDS0066 (3) EDS0068 (3)



       Paul Alfille (