DS2404(3) manual page

[.]XXXXXXXXXXXX[XX][/[ alarm | auto | cycle | date | delay | interval | memory | pages/page.[0-15|ALL] | readonly/[memory|clock|cycle|interval] | memory | pages/page.[0-15|ALL] | readonly/[memory|clock|cycle|interval] | running | set_alarm | start | trigger/[cycle,date,interval,udate,uinterval] | udate | uinterval | address | crc8 | id | locator | present | r_address | r_id | r_locator | type ]]

[.]XXXXXXXXXXXX[XX][/[ alarm | auto | cycle | date | delay | interval | memory | pages/page.[0-15|ALL] | readonly/[memory|clock|cycle|interval] | running | set_alarm | start | trigger/[cycle,date,interval,udate,uinterval] | udate | uinterval | address | crc8 | id | present | type ]]

Special Properties

alarm

read-write, unsigned integer (0-111)
Alarm state of the DS2404 (3) triggered by time or counter events. Reading the alarm state clears the alarm.
The alarm value is of the form CIR, where:

C: cycle counter alarm
0 no
1 yes
I: interval timer alarm
0 no
1 yes
R: real-time clock alarm
0 no
1 yes

auto

read-write, yes-no
Flag for mode of interval counter operation. 0=manual 1=auto
See the datasheet for details.

read-write, ascii
26 character date representation of the udate value. Increments once per second while running
Actual internal representation has higher precision.
Cannot be altered if readonly/clock is set.
Setting date to a null string will put the current system time.
Accepted date formats are:
Sat[urday] March 12 12:23:59 2001

Apr[il] 4 9:34:56 2002

3/23/04 23:34:57

current locale setting (your system’s format)

delay

read-write, yes-no
Flag for adding a delay to cycle counter. 0=short 1-long
See the datasheet under "IDEL" for details.

interval

read-write, date
Interval timer value, represented as a date string. More typically will be used as uinterval to read the actual elapsed seconds.

memory

read-write, binary
512 bytes of memory. The readonly/memory flag prevents further change.

pages/page.0 ... pages/page.15 pages/page.ALL

read-write, yes-no
Memory is split into 16 pages of 32 bytes each. The readonly/memory flag prevents further change. ALL is an aggregate of the pages. Each page is accessed sequentially.

readonly/[memory|clock|interval|cycle]

read-write, yes-no
Permanently protect part of the chip’s function from alteration.

readonly/memory: page.X and memory
readonly/clock: date and udate
readonly/interval: interval
readonly/cycle: cycle

running

read-write, yes-no
State of the clock. 0=off 1=running.

set_alarm

read-write, unsigned integer (0-111)
Which of the alarm triggers are enabled in the DS2404 (3)
The set_alarm value is of the form CIR, where:

C: cycle counter alarm
0 no
1 yes
I: interval timer alarm
0 no
1 yes
R: real-time clock alarm
0 no
1 yes

start

read-write, yes-no
Flag for starting the interval counter operation if not in auto mode. 0=stop 1=start
See the datasheet for details.

trigger/[cycle,date,interval,udate,uinterval]

read-write,varies
Target value that will trigger the alarm if the corresponding set_alarm field is set.
The format is the same as the similarly named field (i.e. date for trigger/date )

udate

read-write, unsigned integer
Time represented as a number. udate increments once per second, while running is on.
Usually set to unix time standard: number of seconds since Jan 1, 1970. The date field will be the unix representation of udate and setting either will change the other.

uinterval

read-write, unsigned interval
Similar to the udate field, except corresponds to the interval value.

Standard Properties

address

r_address

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 labeling.

crc8

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

family

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

id

r_id

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.

locator

r_locator

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

read-only, yes-no
Is the device currently present on the 1-wire bus?
Note, this means that each hex byte (2 characters) is reversed, not the text string.

type

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

Alarms

None implemented.

Description

1-Wire

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

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

The 1-wire bus is accessed via one of a number of serial, parallel or USB adapters.

OWFS design

OWFS is a suite of programs that fundementally 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 files.

There is optional data caching to improved performance, but possible confusion over stale data.

Ds1427 Ds1994 Ds2404 Ds2404s

The DS1427 (3) , DS1994 (3) , DS2404 (3) , and DS2404S (3) family of 1-wire devices includes clock functions, with timers, memory, counters and alarms. It is possible to write-protect regians of memory. Uses include software or hardware timing and control.

Chips

Both the DS2404 (3) and DS2404S (3) have 1-wire and 3-wire interfaces, which might be useful for transfering data between the 2 buses. They act as a passive slave to both busses. The DS2404 (3) and DS2404S (3) require an external source of power and an external crystal. They also offer a reset and 1HZ clock pin.

iButtons

Both the DS1427 and DS1994 offer the memory, alarms, and clock function in iButton format. Because the iButton is a complete sealed package, battery and crystal are internal. Everything is access via the 1-wire interface.