PSD9342V10MT Просмотр технического описания (PDF) - STMicroelectronics

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PSD9342V10MT

Flash PSD, 3.3V Supply, for 8-bit MCUs 2 Mbit + 256 Kbit Dual Flash Memories and 64 Kbit SRAM

STMicroelectronics 

PSD834F2V

ory sector(s). Before and during Erase time-out,

any instruction other than Suspend Sector Erase

and Resume Sector Erase instructions abort the

cycle that is currently in progress, and reset the

device to Read mode. It is not necessary to pro-

gram the Flash memory sector with 00h as the

PSD does this automatically before erasing

(byte=FFh).

During a Sector Erase, the memory status may be

checked by reading the Error Flag (DQ5) bit, the

Toggle Flag (DQ6) bit, and the Data Polling Flag

(DQ7) bit, as detailed in the section entitled “Pro-

gramming Flash Memory”, on page 19.

During execution of the Erase cycle, the Flash

memory accepts only Reset and Suspend Sector

Erase instructions. Erasure of one Flash memory

sector may be suspended, in order to read data

from another Flash memory sector, and then re-

sumed.

Suspend Sector Erase. When a Sector Erase

cycle is in progress, the Suspend Sector Erase in-

struction can be used to suspend the cycle by writ-

ing 0B0h to any address when an appropriate

Sector Select (FS0-FS7 or CSBOOT0-CSBOOT3)

is High. (See Table 7). This allows reading of data

from another 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

instruction executed during an Erase time-out pe-

riod, in addition to suspending the Erase cycle, ter-

minates the time out period.

The Toggle Flag (DQ6) bit 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 (DQ6) bit stops toggling between 0.1 µs 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 exe-

cuted, the following rules apply:

– Attempting to read from a Flash memory sector

that was being erased outputs invalid data.

– Reading from a Flash 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 instructions (Read is an operation and

is allowed).

– If a Reset Flash instruction is received, data in

the Flash memory sector that was being erased

is invalid.

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 address while an appropriate

Sector Select (FS0-FS7 or CSBOOT0-CSBOOT3)

is High. (See Table 7.)

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