DS1904 Maxim, DS1904 Datasheet - Page 8

• Manufacturer Part Number: DS1904
• Description: The DS1904 RTC iButton® is a rugged real-time clock module that can be accessed with minimal hardware
• Manufacturer: Maxim

ROM FUNCTIONS FLOW CHART Figure 7
Serial Number
DS1904 TX
DS1904 TX
DS1904 TX
Family Code
Read ROM
Command
CRC Byte
6 Bytes
1 Byte
33H
?
Y
N
Master TX Bit 63
Master TX Bit 0
Master TX Bit 1
Match ROM
Command
Match ?
Match ?
Match ?
Bit 63
Bit 0
Bit 1
55H
?
Y
Y
Y
Y
N
N
N
N
N
N
N
Function Command
Function Command
8 of 13
Master TX Control
DS1904 TX Bit 63
DS1904 TX Bit 63
Master TX Bit 63
Master TX ROM
DS1904 TX Bit 0
DS1904 TX Bit 0
Master TX Bit 0
DS1904 TX Bit 1
DS1904 TX Bit 1
Master TX Bit 1
Presence Pulse
(SEE FIGURE 5)
DS1904 TX
Search ROM
Reset Pulse
Master TX
Command
Match ?
Match ?
Match ?
Bit 63
Bit 0
F0H
Bit 1
?
Y
Y
Y
Y
N
Skip ROM
Command
CCH
?
Y
N
DS1904