Datasheet
DS28E04-100: 4096-Bit 1-Wire Addressable EEPROM with PIO
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MEMORY FUNCTION EXAMPLE
Write 5 bytes to memory page 1, starting at address 0021h. Read the entire memory and the PIO-related registers.
With only a single DS28E04-100
connected to the bus master, the communication looks like this:
MASTER MODE
DATA (LSB FIRST)
COMMENTS
TX
(Reset)
Reset pulse
RX
(Presence)
Presence pulse
TX
CCh
Issue “Skip ROM” command
TX
0Fh
Issue “Write Scratchpad” command
TX
21h
TA1, beginning offset = 21h
TX
00h
TA2, address = 0021h
TX
<5 data bytes>
Write 5 bytes of data to scratchpad
TX
(Reset)
Reset pulse
RX
(Presence)
Presence pulse
TX
CCh
Issue “Skip ROM” command
TX
AAh
Issue “Read Scratchpad” command
RX
21h
Read TA1, beginning offset = 21h
RX
00h
Read TA2, address = 0021h
RX
05h
Read E/S, ending offset = 00101b, AA, PF = 0
RX
<5 data bytes>
Read scratchpad data and verify
RX
<2 bytes CRC16\>
Read CRC to check for data integrity
TX
(Reset)
Reset pulse
RX
(Presence)
Presence pulse
TX
CCh
Issue “Skip ROM” command
TX
55h
Issue “Copy Scratchpad” command
TX
21h
TA1
TX
00h
TA2 (AUTHORIZATION CODE)
TX
05h
E/S
----
<1-Wire idle high>
Wait 10ms for the copy function to complete
RX
AAh
Read copy status, AAh = success
TX
(Reset)
Reset pulse
RX
(Presence)
Presence pulse
TX
CCh
Issue “Skip ROM” command
TX
F0h
Issue “Read Memory” command
TX
00h
TA1, beginning offset = 00h
TX
00h
TA2, address = 0000h
RX
<550 data bytes>
Read the entire memory
TX
(Reset)
Reset pulse
RX
(Presence)
Presence pulse