10.5.1 Functional

The Write User Zone command $B0 allows data to be written into the device's currently selected user zone (the procedure for selecting a user zone is described below.

The maximum numbers of bytes that may be written in a single write operation is $10, which corresponds to the EEPROM page size. Each data byte within a page must be loaded only once. In Anti-Tearing mode, the maximum value for N is $08 for all devices. A write in Anti-Tearing mode is activated with the Set User Zone command with the anti-tearing option (00 B4 0B zz 00); all subsequent writes to the user zone will be in Anti-Tearing mode.

When a Write User Zone command is sent in Authentication mode or Encryption mode, the data are saved in a buffer until a cryptographic checksum is received. The host must send the checksum it has computed immediately after the Write User Zone command. If the checksum is valid, CryptoMemory® writes the data; if the checksum is incorrect, the data are discarded and the cryptographic engine is reset.

If the host is not allowed to write in the zone, the device will return the "Command Unauthorized" code ($69 $00) after it has received the P3 byte.