8.9.1 Functional

Figure 8-9. Read User Zone Command Functional Description

The Read User Zone command ($B2) allows reading of data from the device's currently selected user zone (the procedure for selecting a user zone is described in section 8.10 System Write: $B4).

The data byte address to be read is defined by Address 1 and Address 2 in the command and is internally incremented following the transmission of each data byte. The value N defines how many bytes CryptoMemory® will read; a value of zero will result in 256 bytes read. The host, however, may cease clocking the device and end the transmission with a NACK and stop at any time prior to receiving all N bytes. During a read operation, the address will roll over from the last byte of the current zone to the first byte of the same zone.

If the host is not allowed to read the zone, the device will not acknowledge the N byte.
Figure 8-10. Read User Zone Command Structure
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