DSM2180F3 datasheet(24/63 Pages) STMICROELECTRONICS

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DSM2180F3

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Flash memory sector may be suspended, in order

to read data from another Flash memory sector,

and then resumed.

The address provided with the initial Flash Sector

Erase command sequence (Table 5) must select

the first desired sector (FS0 - FS7) to erase. Sub-

sequent sector erase commands that are append-

ed on within the time-out period must be

addressed to other desired segments (FS0 - FS7).

Suspend Sector Erase. When a Sector Erase

cycle is in progress, the Suspend Sector Erase in-

struction sequence can be used to suspend the

cycle by writing 0B0h to any address when an ap-

propriate Sector Select (FS0-FS7) is selected

(See Table 5). This allows reading of data from an-

other Flash memory sector after the Erase cycle

has been suspended. Suspend Sector Erase is

accepted only during an Erase cycle and defaults

to Read mode. A Suspend Sector Erase instruc-

tion sequence executed during an Erase time-out

period, in addition to suspending the Erase cycle,

terminates the time out period.

The Toggle Flag (DQ6) bit stops toggling when the

device 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 (DQ6) bit stops toggling between 0.1 µs and

15 µs after the Suspend Sector Erase instruction

sequence has been executed. The device is then

automatically set to Read mode.

If an Suspend Sector Erase instruction sequence

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 Re-

set Flash instruction sequences (Read is an op-

eration and is allowed).

– If a Reset Flash instruction sequence is re-

ceived, data in the Flash memory sector that

was being erased is invalid.

Resume Sector Erase. If

Suspend

Sector

Erase instruction sequence was previously exe-

cuted, the erase cycle may be resumed with this

instruction sequence. The Resume Sector Erase

instruction sequence consists of writing 030h to

any address while an appropriate Sector Select

(FS0-FS7) is active. (See Table 5.)

Flash Memory Sector Protect.

Each Flash memory sector can be separately pro-

tected against Program and Erase cycles. Sector

Protection provides additional data security be-

cause it disables all Program or Erase cycles. This

mode can be activated through the JTAG Port or a

Device Programmer. Sector protection can be se-

lected for each sector using PSDsoft Express.

This automatically protects selected sectors when

the device is programmed through the JTAG Port

or a Device Programmer. Flash memory sectors

can be unprotected to allow updating of their con-

tents using the JTAG Port or a Device Program-

mer. The DSP can read (but cannot change) the

sector protection bits.

Any attempt to program or erase a protected Flash

memory sector is ignored by the device. The Verify

operation results in a read of the protected data.

This allows a guarantee of the retention of the Pro-

tection status.

The sector protection status can be read by the

DSP through the Flash memory protection regis-

ters (in the

csiop block) as defined in Table 7.

Table 7. Sector Protection/Security Bit Definition – Flash Protection Register

Note: 1. Bit Definitions:

Sec<i>_Prot 1 = Flash memory sector <i> is write protected.

Sec<i>_Prot 0 = Flash memory sector <i> is not write protected.

Table 8. Security Bit Definition

Note: 1. Bit Definitions:

1 = Security Bit in device has been set.

Bit 7

Bit 6

Bit 5

Bit 4

Bit 3

Bit 2

Bit 1

Bit 0

Sec7_Prot

Sec6_Prot

Sec5_Prot

Sec4_Prot

Sec3_Prot

Sec2_Prot

Sec1_Prot

Sec0_Prot

Bit 7

Bit 6

Bit 5

Bit 4

Bit 3

Bit 2

Bit 1

Bit 0

Security_Bit

not used

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