Datasheet

DS1683
Total-Elapsed-Time and Event Recorder with Alarm
9Maxim Integrated
If the Password Value has been changed from the factory
default setting, the user has to enter this new password
value into the PWE registers after a power cycle in order
to unlock the memory again.
See Figure 3 for examples of writing the 4-byte Password
Value and the 4-byte Password Entry value.
User Memory
The DS1683 has 16 bytes of user-programmable,
EEPROM memory. User memory is set to read-only if
the correct password is not entered into the Password
Entry Bytes. If the correct password is entered into the
Password Entry Bytes, the data can be written to the User
Memory and stored in EEPROM with the correct I
2
C write
command.
Figure 3. Password Value and Password Entry I
2
C Examples
COMMUNICATIONS KEY
S
NOTES
P
Sr
A
N
START
8-BIT ADDRESS OR DATA
REPEATED
START
STOP
ACK
NOT
ACK
WHITE BOXES INDICATE THE MASTER IS
CONTROLLING SDA
SHADED BOXES INDICATE THE SLAVE IS
CONTROLLING SDA
WRITE THE 4-BYTE PASSWORD VALUE (REGISTERS 1Ah THROUGH 1Dh) WITH A SINGLE TRANSACTION TO SLAVE ADDRESS D6h
WRITE THE 4-BYTE PASSWORD ENTRY (REGISTERS 02h THROUGH 05h) WITH A SINGLE TRANSACTION TO SLAVE ADDRESS D6h
XXXXXXXX
S 1101 10 AABYTE 1 A
BYTE 4 AP
1) ALL BYTES ARE SENT MOST SIGNIFICANT BIT FIRST.
2) THE FIRST BYTE SENT AFTER A START CONDITION
IS ALWAYS THE SLAVE ADDRESS FOLLOWED BY THE
READ/WRITE BIT.
1000011001 BYTE 2 A
S 1101 10 AABYTE 1 A1000001000 BYTE 2 A
BYTE 3 A
BYTE 4 APBYTE 3 A