Datasheet

Figure 13. ROM Commands Flowchart
MASTER Tx
ROM COMMAND
DS
18B20 Tx PRESENCE PULSE
MASTER Tx RESET PULSE
INITIALIZATION
SEQUENCE
33h READ
ROM
COMMAND
55
h MATCH
ROM
COMMAND
F
0h
SEARCH ROM
COMMAND
ECh
ALARM SEARCH
COMMAND
CCh
SKIP ROM
COMMAND
N
Y
N
Y
N
Y
N
Y
N
Y
MASTER Tx
BIT 0
DS18B
20 Tx BIT 0
DS18B20 Tx BIT 0
MASTER Tx BIT 0
BIT 0
MATCH ?
BIT 0
MATCH ?
DEVICE(S)
WITH ALARM
FLAG SET ?
N
Y
N
Y
N
Y
N
MASTER Tx
BIT
1
DS18B
20 Tx BIT 1
DS18B
20 Tx BIT 1
MASTER Tx BIT 1
BIT 1
MATCH?
BIT 1
MATCH?
N
Y Y
N
DS18B20 Tx BIT 63
DS
18B20
Tx BIT 63
MASTER Tx BIT
63
MASTER Tx
BIT 63
DS18B
20 Tx BIT 0
DS18B20 Tx BIT 0
MASTER TX BIT 0
BIT 63
MATCH?
BIT 63
MATCH
?
N
Y Y
N
DS18B20
TX
FAMILY CODE 1
BYTE
DS18B20 Tx
SERIAL NUMBER
6 BYTES
DS18B20 Tx
CRC BYTE
MASTER Tx FUNCTION
COMMAND (FIGURE 14)
DS18B20 Programmable Resolution
1-Wire Digital Thermometer
www.maximintegrated.com
Maxim Integrated │ 13