RW1990 needs longer recovery time to write new data.
This was originally developed as a means of detecting cloned iButtons for an access control application. If I try to write an invalid ID (eg bad CRC) to an iButton, then read it and I read a bad CRC I consider the iButton a clone and do not open the lock.
Operation was investigated using a DSO to observe pulse timing correlated with write success. Tested on three differently sourced RW1990, two different case markings.
RW1990 needs longer recovery time to write new data.
This was originally developed as a means of detecting cloned iButtons for an access control application. If I try to write an invalid ID (eg bad CRC) to an iButton, then read it and I read a bad CRC I consider the iButton a clone and do not open the lock.
Operation was investigated using a DSO to observe pulse timing correlated with write success. Tested on three differently sourced RW1990, two different case markings.
Owen