1DS28EC20(3)                  One-Wire File System                  DS28EC20(3)
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3
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NAME

6       DS28EC20 - EEPROM (20 kBit)
7

SYNOPSIS

9       Erasable programmable read-only memory (EEPROM)
10
11       43  [.]XXXXXXXXXXXX[XX][/[  memory  | pages/page.[0-79|ALL] | address |
12       crc8 | id | locator | r_address | r_id | r_locator | type ]]
13

FAMILY CODE

15       23 DS28EC20
16

SPECIAL PROPERTIES

18   memory
19       read-write, binary
20       512 bytes of memory. Initially all bits are set to 1. Writing zero per‐
21       manently alters the memory.
22
23   pages/page.0 ... pages/page.79 pages/page.ALL
24       read-write, yes-no
25       Memory is split into 80 pages of 32 bytes each.  ALL is an aggregate of
26       the pages. Each page is accessed sequentially.
27

STANDARD PROPERTIES

29   address
30   r_address
31       read-only, ascii
32       The entire 64-bit unique ID. Given as  upper  case  hexadecimal  digits
33       (0-9A-F).
34       address starts with the family code
35       r address is the address in reverse order, which is often used in other
36       applications and labeling.
37
38   crc8
39       read-only, ascii
40       The 8-bit error correction portion. Uses cyclic redundancy check.  Com‐
41       puted  from the preceding 56 bits of the unique ID number. Given as up‐
42       per case hexadecimal digits (0-9A-F).
43
44   family
45       read-only, ascii
46       The 8-bit family code. Unique to each type of device.  Given  as  upper
47       case hexadecimal digits (0-9A-F).
48
49   id
50   r_id
51       read-only, ascii
52       The 48-bit middle portion of the unique ID number. Does not include the
53       family code or CRC. Given as upper case hexadecimal digits (0-9A-F).
54       r id is the id in reverse order, which is often used in other  applica‐
55       tions and labeling.
56
57   locator
58   r_locator
59       read-only, ascii
60       Uses  an  extension  of the 1-wire design from iButtonLink company that
61       associated 1-wire physical connections with a unique  1-wire  code.  If
62       the  connection is behind a Link Locator the locator will show a unique
63       8-byte number (16 character hexadecimal) starting with family code FE.
64       If no Link Locator is between the device and the  master,  the  locator
65       field will be all FF.
66       r locator is the locator in reverse order.
67
68   present (DEPRECATED)
69       read-only, yes-no
70       Is the device currently present on the 1-wire bus?
71
72   type
73       read-only, ascii
74       Part  name  assigned by Dallas Semi. E.g.  DS2401 Alternative packaging
75       (iButton vs chip) will not be distiguished.
76

ALARMS

78       None.
79

DESCRIPTION

81   1-Wire
82       1-wire is a wiring protocol and series of devices designed and manufac‐
83       tured  by  Dallas  Semiconductor, Inc. The bus is a low-power low-speed
84       low-connector scheme where the data line can also provide power.
85
86       Each device is uniquely and unalterably  numbered  during  manufacture.
87       There  are a wide variety of devices, including memory, sensors (humid‐
88       ity, temperature, voltage, contact, current), switches, timers and data
89       loggers.  More complex devices (like thermocouple sensors) can be built
90       with these basic devices. There are also 1-wire devices that  have  en‐
91       cryption included.
92
93       The  1-wire  scheme uses a single bus master and multiple slaves on the
94       same wire. The bus master initiates all communication. The  slaves  can
95       be individually discovered and addressed using their unique ID.
96
97       Bus  masters come in a variety of configurations including serial, par‐
98       allel, i2c, network or USB adapters.
99
100   OWFS design
101       OWFS is a suite of programs that designed to make the  1-wire  bus  and
102       its  devices easily accessible. The underlying principle is to create a
103       virtual filesystem, with the unique ID being the directory, and the in‐
104       dividual  properties of the device are represented as simple files that
105       can be read and written.
106
107       Details of the individual slave or master design are  hidden  behind  a
108       consistent interface. The goal is to provide an easy set of tools for a
109       software designer to create monitoring or control  applications.  There
110       are some performance enhancements in the implementation, including data
111       caching, parallel access to bus masters, and aggregation of device com‐
112       munication.  Still the fundamental goal has been ease of use, flexibil‐
113       ity and correctness rather than speed.
114
115   DS28EC20
116       The DS28EC20 (3) is used for storing memory which should  be  available
117       even  after  a  reset  or  power  off. It's main advantage is for audit
118       trails (i.e. a digital purse).  OWFS system handles this automatically.
119

ADDRESSING

121       All 1-wire devices are factory assigned a unique 64-bit  address.  This
122       address is of the form:
123
124       Family Code
125              8 bits
126
127       Address
128              48 bits
129
130       CRC    8 bits
131
132       Addressing under OWFS is in hexadecimal, of form:
133
134              01.123456789ABC
135
136       where 01 is an example 8-bit family code, and 12345678ABC is an example
137       48 bit address.
138
139       The dot is optional, and the CRC code can  included.  If  included,  it
140       must be correct.
141

DATASHEET

143       http://datasheets.maxim-ic.com/en/ds/DS28EC20.pdf
144

SEE ALSO

146   Programs
147       owfs  (1)  owhttpd  (1)  owftpd  (1)  owserver (1) owdir (1) owread (1)
148       owwrite (1) owpresent (1) owtap (1)
149
150   Configuration and testing
151       owfs (5) owtap (1) owmon (1)
152
153   Language bindings
154       owtcl (3) owperl (3) owcapi (3)
155
156   Clocks
157       DS1427 (3) DS1904 (3) DS1994 (3) DS2404  (3)  DS2404S  (3)  DS2415  (3)
158       DS2417 (3)
159
160   ID
161       DS2401 (3) DS2411 (3) DS1990A (3)
162
163   Memory
164       DS1982  (3)  DS1985  (3)  DS1986  (3)  DS1991 (3) DS1992 (3) DS1993 (3)
165       DS1995 (3) DS1996 (3) DS2430A (3) DS2431  (3)  DS2433  (3)  DS2502  (3)
166       DS2506 (3) DS28E04 (3) DS28EC20 (3)
167
168   Switches
169       DS2405 (3) DS2406 (3) DS2408 (3) DS2409 (3) DS2413 (3) DS28EA00 (3) In‐
170       fernoEmbedded (3)
171
172   Temperature
173       DS1822 (3) DS1825 (3) DS1820 (3) DS18B20 (3)  DS18S20  (3)  DS1920  (3)
174       DS1921  (3) DS1821 (3) DS28EA00 (3) DS28E04 (3) EDS0064 (3) EDS0065 (3)
175       EDS0066 (3) EDS0067 (3) EDS0068 (3) EDS0071 (3)  EDS0072  (3)  MAX31826
176       (3)
177
178   Humidity
179       DS1922 (3) DS2438 (3) EDS0065 (3) EDS0068 (3)
180
181   Voltage
182       DS2450 (3)
183
184   Resistance
185       DS2890 (3)
186
187   Multifunction (current, voltage, temperature)
188       DS2436  (3)  DS2437  (3)  DS2438  (3)  DS2751 (3) DS2755 (3) DS2756 (3)
189       DS2760 (3) DS2770 (3) DS2780 (3) DS2781 (3) DS2788 (3) DS2784 (3)
190
191   Counter
192       DS2423 (3)
193
194   LCD Screen
195       LCD (3) DS2408 (3)
196
197   Crypto
198       DS1977 (3)
199
200   Pressure
201       DS2406 (3) TAI8570 (3) EDS0066 (3) EDS0068 (3)
202
203   Moisture
204       EEEF (3) DS2438 (3)
205

AVAILABILITY

207       http://www.owfs.org
208

AUTHOR

210       Christian Magnusson (mag@mag.cx)
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214OWFS Manpage                         2003                          DS28EC20(3)
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