DS2423

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MEMORY FUNCTION EXAMPLE

Example: Write two data bytes to memory location 0026 and 0027. Read entire memory.

MASTER MODE

DATA (LSB FIRST)

COMMENTS

TX

Reset

Reset pulse (480-960 µs)

RX

Presence

Presence pulse

TX

CCh

Issue “skip ROM” command

TX

0Fh

Issue “write scratchpad” command

TX

26h

TA1, beginning offset=26h

TX

00h

TA2, address=0026h

TX

<2 data bytes>

Write 2 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

26h

Read TA1, beginning offset=26h

RX

00h

Read TA2, address=0026h

RX

07h

Read E/S, ending offset=7h, flags=0h

RX

<2 data bytes>

Read scratchpad data and verify

TX

Reset

Reset pulse

RX

Presence

Presence pulse

TX

CCh

Issue “skip ROM” command

TX

5Ah

Issue “copy scratchpad” command

TX

26h

TX

00h

TX

07h

TA1

TA2

AUTHORIZATION CODE

E/S

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=0

TX

00h

TA2, address=0000h

RX

<512 bytes>

Read entire memory

TX

Reset

Reset pulse

RX

Presence

Presence pulse, done