Instructions
M95640-W M95640-R M95640-DF
6.9
Read Lock Status (available only in M95640-D devices)
The Read Lock Status instruction (see Table 4) is used to check whether the Identification
Page is locked or not in Read-only mode. The Read Lock Status sequence is defined with
the Chip Select (S) first driven low. The bits of the instruction byte and address bytes are
then shifted in on Serial Data Input (D). Address bit A10 must be 1, all other address bits are
Don't Care. The Lock bit is the LSB (least significant bit) of the byte read on Serial Data
Output (Q). It is at “1” when the lock is active and at “0” when the lock is not active. If Chip
Select (S) continues to be driven low, the same data byte is shifted out. The read cycle is
terminated by driving Chip Select (S) high.
The instruction sequence is shown in Figure 16.
Figure 16. Read Lock Status sequence
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Doc ID 16877 Rev 16
STMICROELECTRONICS [ ST ]
