Datasheet

DS2430A
8 of 19
MEMORY FUNCTION FLOW CHART Figure 6 (continued)
READ APPLICATION REGISTER [C3h]
This command is used to read the application register or the register scratchpad. As long as the
application register is not yet locked, the DS2430A transmits data from the register scratchpad. After the
application register is locked the DS2430A transmits data from the application register, making the
register scratchpad inaccessible for reading. The contents of the status register indicate where the data
received with this command came from. After issuing the Read Application Register command, the
master must provide the 1-byte starting address from where data is to be read. The DS2430A
automatically increments the address after every byte read by the master. After the data at address 07h
has been read, the address counter wraps around to 00h for the next byte and reading continues until the
master sends a Reset Pulse.
COPY & LOCK APPLICATION REGISTER [5Ah]
After the data stored in the register scratchpad has been verified the master may send the Copy & Lock
Application Register command followed by a validation key of A5h to transfer the contents of the entire
register scratchpad to the application register and to simultaneously write-protect it. The master may
cancel this command by sending a Reset Pulse instead of the validation key. After the validation key is
transmitted, the data line must be held above V
PUPmin
for at least t
PROG
. Once t
PROG
has expired, the
application register will contain the data of the register scratchpad. Further write accesses to the
application register will be denied. The Copy & Lock Application Register command can only be
executed once.
NOT RECOMMENDED FOR NEW DESIGNS