Rainbow-electronics DS2409 Bedienungsanleitung PDF herunterladen (Seite 14)

DS2409

14 of 18

USAGE EXAMPLE

Configuration: A bus master controls a MicroLAN consisting of a trunk with many DS2409s that create

branches. Each of the DS2409s has a DS2430A connected to its auxiliary output to label its physical

location in the network (see Figure 10). iButton devices are constantly arriving at or departing from the

branches.

Task: Identify one branch where an iButton has arrived and get the branch’s physical location. Determine

the population on that particular branch.

STEP MASTER MODE DATA (LSB FIRST) COMMENTS

1 TX Reset Reset pulse (480µs to 960µs)

2 RX Presence Presence pulse

3 TX ECh Issue “conditional search ROM” command

4 RX/RX/TX for each of the 64 ROM bits Identify and access one of the qualifying devices

5 TX 33h Issue Smart-On Auxiliary command

6 TX FFh Send reset stimulus

7 RX <data byte>* Get reset response byte with presence info

8 RX 33h Get confirmation byte

9 TX CCh Issue “skip ROM” command

10 TX F0h Issue “read memory” command

11 RX <32 data bytes> Get branch location information (DS2430A)

12 TX Reset Reset pulse

13 RX Presence Presence pulse

14 TX 55h Issue “Match ROM” command

15 TX <8 byte ROM ID> Access the previously identified coupler

16 TX CCh Issue Smart-On Main command

17 TX FFh Send reset stimulus

18 RX <data byte>* Get reset response byte with presence info

19 RX CCh Get confirmation byte

20 TX F0h Issue “search ROM” command

21 RX/RX/TX for each of the 64 ROM bits Identify one of the devices connected

22 TX Reset Reset pulse

23 RX Presence Presence pulse

24 TX 55h Issue “Match ROM” command

25 TX <8 byte ROM ID> Access the previously identified coupler

26 TX 66h Send all lines off command

27 RX 66h Get confirmation byte

28 TX Reset Reset pulse

29 RX Presence Presence pulse

repeat steps 12 to 21 for each of the remaining devices on the branch of the identified coupler

* 00h or 01h if presence pulse, FFh if no presence pulse

NOTE:

The sequence of steps 12 to 21 logically decouples all other devices residing on the trunk from

responding to the search ROM command. The All Lines Off command is required to clear the event flag

that made the device respond to the conditional search command.

1 2 ... 9 10 11 12 13 14 15 16 17 18

Kommentare zu diesen Handbüchern

Keine Kommentare

Rainbow-electronics DS2409 Bedienungsanleitung Seite 14

Kommentare zu diesen Handbüchern