DS1923 Maxim, DS1923 Datasheet - Page 49

• Manufacturer Part Number: DS1923
• Description: The DS1923 temperature/humidity logger iButton® is a rugged, self-sufficient system that measures temperature and/or humidity and records the result in a protected memory section
• Manufacturer: Maxim

With only a single device connected to the bus master,
the communication of step 2 looks like this:
Step 3: Start the new mission.
With only a single device connected to the bus master,
the communication of step 3 looks like this:
MASTER MODE
MASTER MODE
Hygrochron Temperature/Humidity Logger
______________________________________________________________________________________
Rx
Rx
Rx
Rx
Rx
Rx
Rx
Rx
Rx
Rx
Tx
Tx
Tx
Tx
Tx
Tx
Tx
Tx
Tx
Tx
Tx
Tx
Tx
Tx
Tx
Tx
Tx
Tx
Tx
Tx
Tx
Tx
Tx
Tx
iButton with 8KB Data-Log Memory
DATA (LSB FIRST)
DATA (LSB FIRST)
<25 Data Bytes>
<32 Data Bytes>
<7 FFh Bytes>
<8 FFh Bytes>
<8 FFh Bytes>
(Presence)
(Presence)
(Presence)
(Presence)
(Presence)
(Presence)
(Reset)
(Reset)
(Reset)
(Reset)
(Reset)
(Reset)
CCh
CCh
AAh
CCh
CCh
CCh
0Fh
00h
02h
00h
02h
1Fh
99h
00h
02h
1Fh
FFh
If step 3 was successful, the MIP bit in the General
Status register is 1, the MEMCLR bit is 0, and the
Mission Start Delay counts down.
Reset pulse
Presence pulse
Issue “Skip ROM” command
Issue “Write Scratchpad” command
TA1, beginning offset = 00h
TA2, address = 0200h
Write 25 bytes of data to scratchpad
Write through the end of the scratchpad
Reset pulse
Presence pulse
Issue “Skip ROM” command
Issue “Read Scratchpad” command
Read TA1, beginning offset = 00h
Read TA2, address = 0200h
Read E/S, ending offset = 1Fh, flags = 0h
Read scratchpad data and verify
Reset pulse
Presence pulse
Issue “Skip ROM” command
Issue “Copy Scratchpad” command
TA1
TA2
E/S
Send dummy password
Reset pulse
Presence pulse
Reset pulse
Presence pulse
Issue “Skip ROM” command
Issue “Start Mission” command
Send dummy password
Send dummy byte
Reset pulse
Presence pulse
(AUTHORIZATION CODE)
COMMENTS
COMMENTS
49