Datasheet

DS1822-PAR
11 of 19
ROM COMMANDS FLOW CHART Figure 9
CCh
SKIP ROM
COMMAND
MASTER T
X
RESET PULSE
DS1822-PAR T
X
PRESENCE
PULSE
MASTER T
X
ROM
COMMAND
33h
READ ROM
COMMAND
55h
MATCH ROM
COMMAND
F0h
SEARCH ROM
COMMAND
ECh
ALARM SEARCH
COMMAND
MASTER T
X
BIT 0
BIT 0
MAT
C
H?
MASTER T
X
BIT 1
BIT 1
MATCH?
BIT 63
MATCH?
MASTER T
X
BIT 63
N
Y
Y Y Y
Y
N N
N
N
N
N
N
Y
Y
Y
BIT 0
MATCH?
BIT 1
MATCH?
BIT 63
MATCH?
N
N
N
Y
Y
Y
DS1822-PAR T
X
FAMILY CODE
1 BYTE
DS1822-PAR T
X
SERIAL NUMBER
6 BYTES
DS1822-PAR T
X
CRC BYTE
DS1822-PAR T
X
BIT 0
DS1822-PAR T
X
BIT 0
MASTER T
X
BIT 0
N
Y
DEVICE(S)
WITH ALARM
FLAG SET?
Initialization
Sequence
MASTER T
X
FUNCTION
COMMAND
(FIGURE 10)
DS1822-PAR T
X
BIT 0
DS1822-PAR T
X
BIT 0
MASTER T
X
BIT 0
DS1822-PAR T
X
BIT 1
DS1822-PAR T
X
BIT 1
MASTER T
X
BIT 1
DS1822-PAR T
X
BIT 63
DS1822-PAR T
X
BIT 63
MASTER T
X
BIT 63