status is read on DQ0. Figure 4 shows a typical flow
for programming the non-volatile bit and Figure 5
shows a typical flow for erasing the non-volatile bits.
The SecSi Sector Protection, Password Locking, Per-
sistent Sector Protection Mode Locking bits are not
erasable after they are programmed. However, the
PPBs are both erasable and programmable (depend-
ing upon device security).
PPB Status
The programming of the PPB for a given sector can be
verified by writing a PPB status verify command to the
device.
PPB Lock Bit Status
The programming of the PPB Lock Bit for a given sec-
tor can be verified by writing a PPB Lock Bit status
verify command to the device.
Unlike Single High Voltage Sector Protect/Unprotect,
the A6 pin no longer functions as the program/erase
selector nor the program/erase margin enable. In-
stead, this function is accomplished by issuing the
specific command for either program (68h) or erase
(60h).
Non-volatile Protection Bit Program And
Erase Flow
The device uses a standard command sequence for
programming or erasing the SecSi Sector Protection,
Password Locking, Persistent Sector Protection Mode
Locking, or Persistent Protection Bits. Unlike devices
that have the Single High Voltage Sector Unpro-
tect/Protect feature, the Am29BDD160 has the stan-
dard two-cycle unlock followed by 60h, which places
the device into non-volatile bit program or erase mode.
Once the mode is entered, the specific non-volatile bit
In asynchronous mode, the DQ6 toggle bit indicates
whether the program or erase sequence is active. (In
synchronous mode, ADV# indicates the status.) If the
DQ6 toggle bit toggles with either OE# or CE#, the
non-volatile bit program or erase operation is in
progress. When DQ6 stops toggling, the value of the
non-volatile bit is available on DQ0.
44
Am29BDD160G
June 7, 2006
SPANSION [ SPANSION ]
