DS2408(3) One-Wire File System DS2408(3)

# [NAME](#NAME)

**DS2408** - 1-Wire 8 Channel Addressable Switch

# [SYNOPSIS](#SYNOPSIS)

8 port switch

**29** \[.]XXXXXXXXXXXX\[XX]\[/\[ **latch.\[0-7|ALL|BYTE]** | **LCD\_M/\[clear|home|screen|message]** | **LCD\_H/\[clear|home|yxscreen|screen|message|onoff]** | **LCD\_H/redefchar.\[0-7|ALL] LCD\_H/redefchar\_hex.\[0-7|ALL]** | **PIO.\[0-7|ALL|BYTE]** | **power** | **sensed.\[0-7|ALL|BYTE]** | **strobe** | **por** | **set\_alarm** | **out\_of\_testmode** |

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

]]

# [FAMILY CODE](#FAMILY_CODE)

*29*

# [SPECIAL PROPERTIES](#SPECIAL_PROPERTIES)

## [latch.0 ... latch.7 latch.ALL latch.BYTE](#latch.0_..._latch.7_latch.ALL_latch.BYTE)

*read-write, binary*  
The 8 pins (PIO) latch a bit when their state changes, either externally, or through a write to the pin.  
Reading the *latch* property indicates that the latch has been set.  
Writing "true" (non-zero) to ANY *latch* will reset them all. (This is the hardware design).  
*ALL* is all *latch* states, accessed simultaneously, comma separated.  
*BYTE* references all channels simultaneously as a single byte. Channel 0 is bit 0.

## [PIO.0 ... PIO.7 PIO.ALL PIO.BYTE](#PIO.0_..._PIO.7_PIO.ALL_PIO.BYTE)

*read-write, yes-no*  
State of the open-drain output ( *PIO* ) pin. 0 = non-conducting (off), 1 = conducting (on).  
Writing zero will turn off the switch, non-zero will turn on the switch. Reading the *PIO* state will return the switch setting. To determine the actual logic level at the switch, refer to the *sensed.0 ... sensed.7 sensed.ALL sensed.BYTE* property.  
*ALL* references all channels simultaneously, comma separated.  
*BYTE* references all channels simultaneously as a single byte. Channel 0 is bit 0.

## [power](#power)

*read-only, yes-no*  
Is the *DS2408* powered parasitically (0) or separately on the Vcc pin (1)?

## [sensed.0 ... sensed.7 sensed.ALL](#sensed.0_..._sensed.7_sensed.ALL)

*read-only, yes-no*  
Logic level at the *PIO* pin. 0 = ground. 1 = high (~2.4V - 5V ). Really makes sense only if the *PIO* state is set to zero (off), else will read zero.  
*ALL* references all channels simultaneously, comma separated.  
*BYTE* references all channels simultaneously as a single byte. Channel 0 is bit 0.

## [strobe](#strobe)

*read-write, yes-no*  
RSTZ Pin Mode Control. Configures RSTZ as either RST input or STRB output:

*0*

configured as RST input (default)

*1*

configured as STRB output

## [por](#por)

*read-write, yes-no*  
Specifies whether the device has performed power-on reset. This bit can only be cleared to 0 under software control. As long as this bit is 1 the device will always respond to a conditional search.

## [out\_of\_testmode](#out_of_testmode)

*write-only, yes-no*  
Write "1" to this property to make sure the device has been properly initialized on startup.

The datasheet says that under some conditions the startup (power-up) will leave the device in the "testmode" state. Any problems with "Channel Access Write" will trigger this property automaticlly, but this property makes explicit initialization possible as well.

## [set\_alarm](#set_alarm)

*read-write, integer unsigned (0-333333333)*  
A number consisting of 9 digits XYYYYYYYY, where:

[X](#X)

select source and logical term  
*0* PIO OR  
*1* latch OR  
*2* PIO AND  
*3* latch AND

[Y](#Y)

select channel and polarity  
*0* Unselected (LOW)  
*1* Unselected (HIGH)  
*2* Selected LOW  
*3* Selected HIGH

All digits will be truncated to the 0-3 range. Leading zeroes are optional. Low-order digit is channel 0.

Example:

100000033

Responds on Conditional Search when latch.1 or latch.0 are set to 1.

222000000

Responds on Conditional Search when sensed.7 and sensed.6 are set to 0.

000000000 (0)

Never responds to Conditional Search.

# [LCD\_H LCD SCREEN PROPERITES](#LCD_H_LCD_SCREEN_PROPERITES)

This mode uses the *DS2408* attached to a Hitachi HD44780 LCD controller in 4-bit mode. See *DATASHEET* for published details. Based on a commercial product from *HobbyBoards* by Erik Vickery.

## [LCD\_H/clear](#LCD_H/clear)

*write-only, yes-no*  
This will *clear* the screen and place the cursor at the start.

## [LCD\_H/home](#LCD_H/home)

*write-only, yes-no*  
Positions the cursor in the *home* (upper left) position, but leaves the current text intact.

## [LCD\_H/screen](#LCD_H/screen)

*write-only, ascii text*  
Writes to the LCD *screen* at the current position.

## [LCD\_H/screenyc](#LCD_H/screenyc)

*write-only, ascii text*  
Writes to an LCD screen at a specified location. The controller doesn't know the true LCD dimensions, but typical selections are: 2x16 2x20 4x16 and 4x20.

Y (row)

range 1 to 2 (or 4)

X (column)

range 1 to 16 (or 20)

There are two formats allowed for the *screenyx* text, either ascii (readable text) or a binary form.

2 binary bytes

The two first characters of the passed string have the line and row: e.g. "\\x02\\x04string" perl string writes "string" at line 2 column 4.

[ascii 2,12:](#ascii)

Two numbers giving line and row: Separate with a comma and end with a colon e.g. "2,4:string" writes "string" at line 2 column 4.

[ascii 12:](#ascii~2)

Single column number on the (default) first line: End with a colon e.g. "12:string" writes "string" at line 1 column 12.

The positions are 1-based (i.e. the first position is 1,1).

## [LCD\_H/onoff](#LCD_H/onoff)

*write-only, unsigned*  
Sets several screen display functions. The selected choices should be added together.

4

Display on

2

Cursor on

1

Cursor blinking

## [LCD\_H/message](#LCD_H/message)

*write-only, ascii text*  
Writes a *message* to the LCD screen after clearing the screen first. This is the easiest way to display a message.

## [LCD\_H/redefchar.0-7|ALL](#LCD_H/redefchar.0-7_ALL)

*write-only, binary*  
Redefines one of 8 user-designed character glyphs for the LCD screen (5x8 pixels).

Each byte defines a horizontal line top to bottom. All 5 pixels corresponds to 0x1F and a blank line is 0x00.

Format is 8 binary bytes.

## [LCD\_H/redefchar\_hex.0-7|ALL](#LCD_H/redefchar_hex.0-7_ALL)

*write-only, ascii*  
Redefines one of 8 user-designed character glyphs for the LCD screen (5x8 pixels).

Each byte defines a horizontal line top to bottom. All 5 pixels corresponds to 0x1F and a blank line is 0x00.

Format is 8 hexadecimal bytes (16 characters).

# [LCD\_M LCD SCREEN PROPERITES](#LCD_M_LCD_SCREEN_PROPERITES)

This mode uses the *DS2408* attached to a Hitachi HD44780 LCD controller in 8-bit mode. See *DATASHEET* for published details. Based on a design from Maxim and a commercial product from *AAG.*

## [LCD\_M/clear](#LCD_M/clear)

*write-only, yes-no*  
This will *clear* the screen and place the cursor at the start.

## [LCD\_M/home](#LCD_M/home)

*write-only, yes-no*  
Positions the cursor in the *home* (upper left) position, but leaves the current text intact.

## [LCD\_M/screen](#LCD_M/screen)

*write-only, ascii text*  
Writes to the LCD *screen* at the current position.

## [LCD\_M/screenyc](#LCD_M/screenyc)

*write-only, ascii text*  
Writes to an LCD screen at a specified location. The controller doesn't know the true LCD dimensions, but typical selections are: 2x16 2x20 4x16 and 4x20.

Y (row)

range 1 to 2 (or 4)

X (column)

range 1 to 16 (or 20)

There are two formats allowed for the *screenyx* text, either ascii (readable text) or a binary form.

2 binary bytes

The two first characters of the passed string have the line and row: e.g. "\\x02\\x04string" perl string writes "string" at line 2 column 4.

[ascii 2,12:](#ascii~3)

Two numbers giving line and row: Separate with a comma and end with a colon e.g. "2,4:string" writes "string" at line 2 column 4.

[ascii 12:](#ascii~4)

Single column number on the (default) first line: End with a colon e.g. "12:string" writes "string" at line 1 column 12.

The positions are 1-based (i.e. the first position is 1,1).

## [LCD\_M/onoff](#LCD_M/onoff)

*write-only, unsigned*  
Sets several screen display functions. The selected choices should be added together.

4

Display on

2

Cursor on

1

Cursor blinking

## [LCD\_M/message](#LCD_M/message)

*write-only, ascii text*  
Writes a *message* to the LCD screen after clearing the screen first. This is the easiest way to display a message.

# [STANDARD PROPERTIES](#STANDARD_PROPERTIES)

See the file man3/standard.3so.

# [ALARMS](#ALARMS)

Use the *set\_alarm* property to set the alarm triggering criteria.

# [DESCRIPTION](#DESCRIPTION)

See the file man3/description.3so.

## [DS2408](#DS2408)

The [**DS2408 (3)**](/man/os/owfs/DS2408.3) allows control of other devices, like LEDs and relays. It extends the **DS2406** to 8 channels and includes memory.  
Alternative switches include the **DS2406, DS2407** and even **DS2450**

# [ADDRESSING](#ADDRESSING)

See the file man3/addressing.3so.

# [DATASHEET](#DATASHEET)

http://pdfserv.maxim-ic.com/en/ds/DS2408.pdf  
http://www.hobby-boards.com/catalog/howto\_lcd\_driver.php  
http://www.maxim-ic.com/appnotes.cfm/appnote\_number/3286

# [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: DS2408(3) from owfs 3.2.4-r10 (Chainguard OS)
Source: https://github.com/owfs/owfs