Motorola MPC533 Reference Manual page 850

UC3F Operation
Table 19-8. Erase Interlock State Descriptions (continued)
State
S4 Erase Operation:
High voltage is applied to the array blocks to erase
the UC3F bit cells, and erase margin reads are
automatically performed by the embedded erase
control logic. During erase the array will not
respond to any address. Accesses to the registers
are allowed. A write to UC3FCTL can change EHV
or HSUS only.
S5 Erase Suspend Operation:
The erase operation is suspended to either read
the array or disable the module. Once HVS reads
as a 0, the erase operation is suspended. Normal
reads to the array can be performed if the module
is enabled; read accesses to locations in blocks
being erased return indeterminate data.
19.3.8.2 Erasing Shadow Information Words
The shadow information words are erased with either the lowest numbered block or small
block 0, depending on the array configuration and the state of SBEN[0]. If the lowest
numbered block in the array does not host a small block, then the shadow information
words are erased with the lowest numbered block. If the lowest numbered block hosts a
small block, then the shadow information words may get erased with small block 0. If
SBEN[0] = 0 for this array configuration, then the shadow information words get erased
with the lowest numbered block. If SBEN[0] = 1 for this same array configuration, then the
shadow information words get erased with small block 0 only.
19.3.8.3 Erase Suspend
The erase operation may be suspended to allow read accesses to the array. Setting the HSUS
bit in the UC3FCTL to a 1 while EHV=1 and HVS=1 forces the array into an erase suspend
state. The deassertion of the HVS bit (HVS = 0) signifies that the erase operation has been
successfully suspended. The HVS bit should negate within 10 ms of asserting the HSUS bit.
While in erase suspend mode, normal read accesses may be performed to the UC3F array
or shadow information words. Reads to the array block or blocks targeted for erase return
indeterminate data since only a partial erase operation has been performed.
The erase operation may be resumed by setting HSUS = 0.
19-28
PRELIMINARY—SUBJECT TO CHANGE WITHOUT NOTICE
Mode
MPC533 Reference Manual
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Transition Requirement
State
S1 T5 Reset.
S2 T7 Write EHV = 0.
S5 T8 Write HSUS = 1 or disable the UC3F
module.
S1 T10 Reset.
S4 T9 Write HSUS = 0 or re-enable the UC3F
module.
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