M39208 datasheet(12/30 Pages) STMICROELECTRONICS

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A12

A16

A17

DQ0 - DQ7

VIL

VIH

VID

VIL

XXX

VID

Protection Activation

VIL

VIH

VIL

VIH

VIL

VIH

VIL

VID

XSA

Verify the protection status:

when DQ0= 1, the sector is

protected

Notes:

X = Don’t care.

SA = Software Address.

Table 8. Flash Sector Protection

A12

A15

A16

A17

DQ0 - DQ7

VID

VIH

VID

VIL

VID

VIH

Activation of Unprotected

Mode

VIL

VIH

VIL

VIH

VIL

VIH

VID

Verify the protection status:

when 00h, the sector is

unprotected

Notes:

X = Don’t care.

SA = Software Address.

Table 9. Flash Unprotection

Erase Suspend Instruction. When a Flash Sector

Erase operation is in progress, the Erase Suspend

instruction may suspend the operation by writing

B0h at any address (see Table 4). This allows

reading of data from another Flash sector while

erase is in progress. Erase suspend is accepted

only during the Flash Sector Erase instruction exe-

cution and defaults to read array mode. An Erase

Suspend instruction entered during an Erase

timeout will, in addition to suspending the erase,

terminates the timeout.

The Toggle bit DQ6 stops toggling when the

M39208 internal logic is suspended. The Toggle bit

status must be monitored at an address out of the

Flash sector being erased. Toggle bit will stop

toggling between 0.1

µs and 15µs after the Erase

Suspend instruction has been written. The M39208

will then automatically be set into Read Flash Block

Memory Array mode.

When erase is suspended, Reading from Flash

sectors being erased will output invalid data, a

Read from Flash sector not being erased is valid.

During an Erase Suspend, the Flash memory will

respond only to Erase Resume and Reset instruc-

tions.

A Reset instruction will definitively abort erasure

and can leave invalid data in the Flash sectors

being erased.

Erase Resume Instruction. If an Erase Suspend

instruction was previously executed, the erase op-

eration may be resumed by this instruction. The

Erase Resume instruction consists of writing 30h

at any address (see Table 4).

FLASH BLOCK SPECIFIC FEATURES

Flash Sector Protection. Each Flash sector can

be separately protected against Program or Erase.

Flash Sector Protection provides additional data

security, as it disables all program or erase opera-

tions. This mode is activated when both A9 and G

are set to VID (12V + 0.5V) and the Flash sector

address is applied on A16 and A17, as shown in

Figure 8 and Table 8.

Flash sector protection is programmed with the

help of a specific sequence of levels applied on EF,

EE, G, A0, A1, A6, A9, A16 and A17; this sequence

includes a verification of the Protection status on

DQ0 as shown in Table 8.

Any attempt to program or erase a protected Flash

sector will be ignored by the device.

Remarks:

– The Verify operation is a read with a simulated

worst case conditions. This allows a guarantee

of the retention of the Protection status

– During the application life, the Sector protection

status can be accessed with a regular Read

instruction without applying a "high voltage" VID

on A9. This instruction is detailed in Table 4.

12/30

M39208

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