Rainbow Electronics DS2404 - Manual (Page 3)

DS2404
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4) skip ROM or 5) search interrupt. After a ROM function sequence has been successfully executed, the
memory functions are accessible and the master may then provide any one of the four memory function
commands (Figure 6).
The “Power Control” section provides for two basic power configurations: battery operate mode and V
CC
operate mode. The battery operate mode utilizes one supply connected to V
BATO
. The V
CC
operate mode
may utilize two supplies; the primary supply connects to V
CC
and a backup supply connects to V
BATB
.
DS2404 BLOCK DIAGRAM Figure 1
COMMUNICATION PORTS
Two communication ports are provided: a 1-Wire and a 3-wire port. The advantages of using the 1-Wire
port are as follows: 1) provides access to the 64-bit lasered ROM, 2) consist of a single communication
signal (I/O), and 3) multiple devices may be connected to the 1-Wire bus. The 1-Wire bus has a
maximum data rate of 16.3kbits/s and requires one 5k
W external pull-up.
The 3-wire port consists of three signals: RST , CLK, and DQ. RST is an enable input, DQ is bidirectional
serial data, and the CLK input is used to clock in or out the serial data. The advantages of using the
3-wire port are 1) high data transfer rate (2MHz), 2) simple timing, and 3) no external pull-up required.