PSD813F1 datasheet(29/110 Pages) STMICROELECTRONICS

29 / 110 page

29/110

PSD813F1

ERASING FLASH MEMORY

Flash Bulk Erase

The Flash Bulk Erase instruction uses six write op-

erations followed by a Read operation of the status

byte of the Bulk Erase instruction is wrong, the

Bulk Erase instruction aborts and the device is re-

set to the Read Flash memory status.

During a Bulk Erase, the memory status may be

checked by reading status bits DQ5, DQ6, and

DQ7, as detailed in section entitled PROGRAM-

MING FLASH MEMORY, page 27. The Error bit

(DQ5) returns a ‘1’ if there has been an Erase Fail-

ure (maximum number of erase cycles have been

executed).

It is not necessary to program the array with 00h

because the PSD will automatically do this before

erasing to 0FFh.

During execution of the Bulk Erase instruction, the

Flash memory will not accept any instructions.

Flash Sector Erase. The Sector Erase instruc-

tion uses six write operations, as described in Ta-

ble 8., page 20. Additional Flash Sector Erase

confirm commands and Flash sector addresses

can be written subsequently to erase other Flash

sectors in parallel, without further coded cycles, if

the additional instruction is transmitted in a shorter

time than the timeout period of about 100 µs. The

input of a new Sector Erase instruction will restart

the time-out period.

The status of the internal timer can be monitored

through the level of DQ3 (Erase time-out bit). If

DQ3 is ‘0’, the Sector Erase instruction has been

received and the timeout is counting. If DQ3 is ‘1’,

the timeout has expired and the PSD is busy eras-

ing the Flash sector(s). Before and during Erase

timeout, any instruction other than Erase suspend

and Erase Resume will abort the instruction and

reset the device to READ mode. It is not neces-

sary to program the Flash sector with 00h as the

PSD will do this automatically before erasing

(byte=FFh).

During a Sector Erase, the memory status may be

checked by reading status bits DQ5, DQ6, and

DQ7, as detailed in section entitled PROGRAM-

MING FLASH MEMORY, page 27.

During execution of the erase instruction, the

Flash block logic accepts only Reset and Erase

Suspend instructions. Erasure of one Flash sector

may be suspended, in order to read data from an-

other Flash sector, and then resumed.

Flash Erase Suspend

When a Flash Sector Erase operation is in

progress, the Erase Suspend instruction will sus-

pend the operation by writing 0B0h to any address

when an appropriate Chip Select (FSi) is true.

(See Table 8., page 20). This allows reading of

data from another Flash sector after the Erase op-

eration has been suspended. Erase suspend is

accepted only during the Flash Sector Erase in-

struction execution and defaults to READ mode.

An Erase Suspend instruction executed during an

Erase timeout will, in addition to suspending the

erase, terminate the time out.

The Toggle Bit DQ6 stops toggling when the PSD

internal logic is suspended. The toggle Bit status

must be monitored at an address within the Flash

sector being erased. The Toggle Bit will stop tog-

gling between 0.1 µs and 15 µs after the Erase

Suspend instruction has been executed. The PSD

will then automatically be set to Read Flash Block

Memory Array mode.

If an Erase Suspend instruction was executed, the

following rules apply:

Attempting to read from a Flash sector that

was being erased will output invalid data.

Reading from a Flash sector that was not

being erased is valid.

The Flash memory cannot be programmed,

and will only respond to Erase Resume and

Reset instructions (READ is an operation and

is OK).

If a Reset instruction is received, data in the

Flash sector that was being erased will be

invalid.

Flash Erase Resume

If an Erase Suspend instruction was previously ex-

ecuted, the erase operation may be resumed by

this instruction. The Erase Resume instruction

consists of writing 030h to any address while an

appropriate Chip Select (FSi) is true. (See Table

8., page 20.)

PSD813F1 датащи(PDF) 29 Page - STMicroelectronics

PSD813F1 датащи(HTML) 29 Page - STMicroelectronics

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 ...More

датащи скачать

ссылки URL