Rainbow Electronics AT45DB642 - Manual (Page 26)

26 AT45DB321E [PRELIMINARY DATASHEET]
8784B–DFLASH–11/2012
8.2.2 Reading the Security Register
To read the Security Register, an opcode of 77h and three dummy bytes must be clocked into the device. After the last
dummy bit has been clocked in, the contents of the Security Register can be clocked out on the SO pin. After the last
byte of the Security Register has been read, additional pulses on the SCK pin will result in undefined data being output
on the SO pin.
Deasserting the CS pin will terminate the Read Security Register operation and put the SO pin into a high-impedance
state.
Figure 8-5. Read Security Register
77h XX XX XX
Data
n
Data
n + 1
CS
Data
n + x
SI
SO
Each transition represents eight bits