OWIN and OWOUT are the commands to be used.

If you would let me know what kind of iButton you are trying to read i could probably help.

Reading the scratchpad does'nt make much sense unless you have written to it.

See IButton datasheet.

for a quick test:

try to read the family code and serial.

When trying to read the memory only send a "SKIP ROM" command first.

rgds