1024-Bit, 1-Wire EEPROM
Memory Function Example
Write to the first 8 bytes of memory page 1. Read the
entire memory.
With only a single DS2431 connected to the bus mas-
ter, the communication looks like this:
MASTER MODE
DATA (LSB FIRST)
COMMENTS
Reset pulse
Tx
Rx
Tx
Tx
Tx
Tx
Tx
Rx
Tx
Rx
Tx
Tx
Rx
Rx
Rx
Rx
Rx
Tx
Rx
Tx
Tx
Tx
Tx
Tx
—
(Reset)
(Presence)
Presence pulse
DS2431
CCh
Issue “Skip ROM” command
Issue “Write Scratchpad” command
TA1, beginning offset = 20h
TA2, address = 0020h
0Fh
20h
00h
<8 Data Bytes>
Write 8 bytes of data to scratchpad
Read CRC to check for data integrity
Reset pulse
<2 Bytes CRC-16>
(Reset)
(Presence)
Presence pulse
CCh
Issue “Skip ROM” command
Issue “Read Scratchpad” command
Read TA1, beginning offset = 20h
Read TA2, address = 0020h
Read E/S, ending offset = 111b, AA, PF = 0
Read scratchpad data and verify
Read CRC to check for data integrity
Reset pulse
AAh
20h
00h
07h
<8 Data Bytes>
<2 Bytes CRC-16>
(Reset)
(Presence)
CCh
Presence pulse
Issue “Skip ROM” command
Issue “Copy Scratchpad” command
TA1
55h
20h
(AUTHORIZATION CODE)
00h
TA2
E/S
07h
<1-Wire Idle High>
AAh
Wait t
for the copy function to complete
PROGMAX
Rx
Tx
Rx
Tx
Tx
Tx
Tx
Rx
Tx
Rx
Read copy status, AAh = success
Reset pulse
(Reset)
(Presence)
CCh
Presence pulse
Issue “Skip ROM” command
Issue “Read Memory” command
TA1, beginning offset = 00h
TA2, address = 0000h
Read the entire memory
Reset pulse
F0h
00h
00h
<144 Data Bytes>
(Reset)
(Presence)
Presence pulse
22 ______________________________________________________________________________________
MAXIM [ MAXIM INTEGRATED PRODUCTS ]
