DS2408_10 Datasheet, PDF(37/39 Page) Maxim Integrated Products

English

English German Russian Spanish Italian Polish Chinese Japanese Korean French Portuguese	Language :

DS2408_10 Datasheet, PDF (37/39 Pages) Maxim Integrated Products – 1-Wire 8-Channel Addressable Switch

◁

After all DS2408s are initialized, perform the search process below as an endless loop:

DS2408

MASTER MODE

Step 4 TX

Step 5 TX

(â)

DATA (LSB FIRST)

(Reset)

(Presence)

ECh

<2 bits>

<1 bits>

<2 bits>

<1 bits>

(â)

F0h

88h

00h

<8 data bytes>

<2 bytes CRC16>

(Reset)

(Presence)

A5h

AAh

(â)

COMMENTS

Reset pulse

Presence pulse

Issue Conditional Search ROM command

Read 2 bits; if both bits are 1, no push button

has been pressed; in this case return to Step

4. If the bit pattern is 01 or 10 or 00, a push

button has been pressed; in this case

continue with Step 5.

Identify and select the LS bit of the ROM ID

of the DS2408 that has responded to the

Conditional Search.

Read 2 bits; this relates to the next bit of the

ROM ID of the participating device(s).

Identify and select the next bit of the ROM ID

of the DS2408 that has responded to the

Conditional Search.

Repeat the previous 2 steps until one device

has been identified and accessed. (see Note

Issue Read PIO Registers command

TA1, target address = 88h

TA2, target address = 0000h

Read register page; the data in the Activity

Latch State Register tells which button has

been pressed.

Read CRC16 and verify correct data

transmission.

Reset pulse

Presence pulse

Issue Resume command

Issue Reset Activity Latch command

Read for verification (AAh = success)

Now, as the device and push button are

identified and the Activity Latch is cleared,

continue at Step 4.

Note 1: For a full description of the Search Algorithm see Application Note 187.

37 of 39

▷