PSD4235G2-12UT datasheet(44/124 Pages) STMICROELECTRONICS

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Erasing Flash memory

PSD4235G2V

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9.2

Suspend Sector Erase

When a Sector Erase cycle is in progress, the Suspend Sector Erase instruction can be

used to suspend the cycle by writing 0B0h to any even address when an appropriate Sector

Select (FS0-FS7 or CSBOOT0-CSBOOT3) is high. (See Table 28). This allows reading of

data from another Flash memory sector after the Erase cycle has been suspended.

Suspend Sector Erase is accepted only during the Flash Sector Erase instruction execution

and defaults to READ mode. A Suspend Sector Erase instruction executed during an Erase

timeout period, in addition to suspending the Erase cycle, terminates the time out period.

The Toggle Flag bit (DQ6/DQ14) stops toggling when the PSD internal logic is suspended.

The status of this bit must be monitored at an address within the Flash memory sector being

erased. The Toggle Flag bit (DQ6/DQ14) stops toggling between 0.1µs and 15 µs after the

Suspend Sector Erase instruction has been executed. The PSD is then automatically set to

READ mode.

If an Suspend Sector Erase instruction was executed, the following rules apply:

●

Attempting to read from a Flash memory sector that was being erased outputs invalid

data.

●

Reading from a Flash memory sector that was not being erased is valid.

●

The Flash memory cannot be programmed, and only responds to Resume Sector

Erase and Reset instructions (READ is an operation and is allowed).

●

If a Reset instruction is received, data in the Flash memory sector that was being

erased is invalid.

9.3

Resume Sector Erase

If a Suspend Sector Erase instruction was previously executed, the Erase cycle may be

resumed with this instruction. The Resume Sector Erase instruction consists of writing 030h

to any even address while an appropriate Sector Select (FS0-FS7 or CSBOOT0-CSBOOT3)

is high. (See Table 28.)

PSD4235G2-12UT Datasheet(PDF) 44 Page - STMicroelectronics