DS1921K# Maxim Integrated Products, DS1921K# Datasheet - Page 38

• Manufacturer Part Number: DS1921K#
• Description: KIT IBUTTON THERMOCHRON
• Manufacturer: Maxim Integrated Products
• Series: iButton®r

Specifications of DS1921K#

• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Memory Size: -
• Memory Type: -
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant

Thermochron iButton
Step 2: Clear the data of the previous mission
Set the EMCLR bit to 1, enable the RTC, and then execute the Clear Memory command. The RTC oscillator must be
stable before the Clear Memory command is issued. Wait 500µs after issuing the Clear Memory command before
proceeding to step 3. This results in the following data to be written to the Status register:
With only a single DS1921G connected to the bus master, the communication of step 2 is as follows:
38
MASTER MODE
______________________________________________________________________________________
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
ADDRESS
DATA
DATA (LSB FIRST)
(Presence)
(Presence)
(Presence)
(Presence)
(Presence)
(Reset)
(Reset)
(Reset)
(Reset)
(Reset)
CCh
CCh
CCh
CCh
AAh
0Eh
0Eh
0Eh
0Eh
0Eh
3Ch
0Fh
02h
40h
02h
40h
55h
02h
Reset pulse (480μs to 960μs)
Presence pulse
Issue Skip ROM command
Issue Write Scratchpad command
TA1, beginning offset = 0Eh
TA2, address = 020Eh
Write status byte to scratchpad
Reset pulse
Presence pulse
Issue Skip ROM command
Issue Read Scratchpad command
Read TA1, beginning offset = 0Eh
Read TA2, address = 020Eh
Read E/S, ending offset = 0Eh, flags = 0h
Read scratchpad data and verify
Reset pulse
Presence pulse
Issue Skip ROM command
Issue Copy Scratchpad command
TA1
TA2
E/S
Reset pulse
Presence pulse
Issue Skip ROM command
Issue Clear Memory command
Reset pulse
Presence pulse
(AUTHORIZATION CODE)
COMMENTS
20Eh
40h