DS2502(3) One-Wire File System DS2502(3)

# [NAME](#NAME)

**DS2502** - Add-Only Memory (1 kBit)

[**DS2502-E48, DS2502-UNW**](#DS2502-E48,)

\- 48-bit Node Address Chip, UniqueWare Add-Only Memory (1 kBit)

[**DS1982, DS1982U**](#DS1982,)

\- Add-Only iButton (1 kBit), UniqueWare iButton (1 kBit)

# [SYNOPSIS](#SYNOPSIS)

EPROM add-only memory.

**09** \[.]XXXXXXXXXXXX\[XX]\[/\[ **memory** | **pages/page.\[0-3|ALL]** |

See the file man3/standard\_mini.3so.

]]

**89** \[.]XXXXXXXXXXXX\[XX]\[/\[ **mac\_e** | **mac\_fw** | **memory** | **pages/page.\[0-3|ALL]** | **project** |

See the file man3/standard\_mini.3so.

]]

# [FAMILY CODE](#FAMILY_CODE)

*09*

DS2502 DS1982

*89*

DS2502-UNW DS2502-E48 DS1982U

# [SPECIAL PROPERTIES](#SPECIAL_PROPERTIES)

## [mac\_e mac\_fw](#mac_e_mac_fw)

*read-only, binary*  
64 bit or 80 bit *media access control* number. Unique, and unrelated to the 1-wire address. It is apparently used for ethernet or FireWire addressing, respectively.

## [memory](#memory)

*read-write, binary*  
128 bytes of memory. Initially all bits are set to 1. Writing zero permanently alters the memory.

## [pages/page.0 ... pages/page.3 pages/page.ALL](#pages/page.0_..._pages/page.3_pages/page.ALL)

*read-write, yes-no*  
Memory is split into 4 pages of 32 bytes each. *ALL* is an aggregate of the pages. Each page is accessed sequentially.

## [project](#project)

*read-only, binary*  
32 bit *project* id. Constant 0x0000 for ethernet and 0x00001128 for firewire. See Datasheets.

# [STANDARD PROPERTIES](#STANDARD_PROPERTIES)

See the file man3/standard.3so.

# [ALARMS](#ALARMS)

None.

# [DESCRIPTION](#DESCRIPTION)

See the file man3/description.3so.

## [DS2502 DS1982](#DS2502_DS1982)

The [**DS2502 (3)**](/man/os/owfs/DS2502.3) is used for write-once incremental storage. It's main advantage is for audit trails (i.e. a digital purse).

The **DS2502-E48** and **DS2502-UNW** are some of the *UniqueWare* class of devices. Some of the memory was preprogramed at the factory. See the datasheet for specifics. The **DS2502** , **DS2505** , and **DS2506** differ in their function by the amount of on-board memory they possess. (The internal protocols are slightly different, but the *OWFS* system handles this automatically.

# [ADDRESSING](#ADDRESSING)

See the file man3/addressing.3so.

# [DATASHEET](#DATASHEET)

http://pdfserv.maxim-ic.com/en/ds/DS2502.pdf  
http://pdfserv.maxim-ic.com/en/ds/DS2502-E48.pdf  
http://pdfserv.maxim-ic.com/en/ds/DS2502-UNW-DS2506S-UNW.pdf  
http://pdfserv.maxim-ic.com/en/ds/DS1982-F3-DS1982-F5.pdf  
http://pdfserv.maxim-ic.com/en/ds/DS1982U-DS1986U.pdf

# [SEE ALSO](#SEE_ALSO)

See the file man3/seealso.3so.

# [AVAILABILITY](#AVAILABILITY)

http://www.owfs.org

# [AUTHOR](#AUTHOR)

Paul Alfille (paul.alfille@gmail.com)

2003 OWFS Manpage

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Document: DS2502(3) from owfs 3.2.4-r8 (Chainguard OS)
Source: https://github.com/owfs/owfs