S29CD032J datasheet(43/76 Pages) SPANSION

43 / 76 page

September 27, 2006 S29CD-J_CL-J_00_B1

S29CD-J & S29CL-J Flash Family

Da ta

Shee t

(Prelim i nar y )

Figure 9.3 PPB Erase Operation

9.3

Persistent Protection Bit Lock Bit

The Persistent Protection Bit Lock Bit is a global volatile bit for all sectors. When set to “1”, it locks all PPBs;

when set to “0”, it allows the PPBs to be changed. There is only one PPB Lock Bit per device.

Notes

1. No software command sequence unlocks this bit unless the device is in the password protection

mode; only a hardware reset or a power-up clears this bit.

2. The PPB Lock Bit must be set only after all PPBs are configured to the desired settings.

9.4

Dynamic Protection Bits

A Dynamic Protection Bit (DYB) is volatile and unique for each sector and can be individually modified. DYBs

only control the protection scheme for unprotected sectors that have their PPBs set to “0”. By issuing the DYB

Set or Clear command sequences, the DYBS are set or cleared, thus placing each sector in the protected or

unprotected state respectively. This feature allows software to easily protect sectors against inadvertent

changes, yet does not prevent the easy removal of protection when changes are needed.

Notes

1. The DYBs can be set or cleared as often as needed with the DYB Write Command.

2. When the parts are first shipped, the PPBs are cleared, the DYBs are cleared, and PPB Lock is

defaulted to power up in the cleared state – meaning the PPBs are changeable. The DYB are also

always cleared after a power-up or reset.

3. It is possible to have sectors that are persistently locked with sectors that are left in the dynamic

state.

4. The DYB Set or Clear commands for the dynamic sectors signify the protected or unprotected state

of the sectors respectively. However, if there is a need to change the status of the persistently

Either poll DQ6 in the

small bank and wait for

it to stop toggling OR

wait 20 ms

DQ0 = 0?

Write 0x60 to WP

Write 0x40 to WP

Read from WP

YES

Done

Error

Write 0xAA to 0x555

Write 0x55 to 0x2AA

Write 0x60 to 0x555

5th attempt?

Note: Reads from the

small bank at this point

return the status of the

operation, not read array

data.

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