BS640HD9V datasheet(41/89 Pages) AMD

41 / 89 page

May 10, 2006 27024B3

Am29BDS128H/Am29BDS640H

D A TA

SH EE T

number of sectors may be from one sector to all sec-

tors. The time between these additional cycles must be

less than tSEA, otherwise erasure may begin. Any

sector erase address and command following the

exceeded time-out, tSEA, may or may not be accepted.

It is recommended that processor interrupts be dis-

abled during this time to ensure all commands are

accepted. The interrupts can be re-enabled after the

last Sector Erase command is written. Any command

other than Sector Erase or Erase Suspend during the

time-out period resets that bank to the read mode. The

system must rewrite the command sequence and any

additional addresses and commands.

The system can monitor DQ3 to determine if the sector

erase timer has timed out (See “DQ3: Sector Erase

Timer” section on page 51.) The time-out begins from

the rising edge of the final WE# pulse in the command

sequence.

When the Embedded Erase algorithm is complete, the

bank returns to reading array data and addresses are

no longer latched. Note that while the Embedded Erase

operation is in progress, the system can read data from

the non-erasing bank. The system can determine the

status of the erase operation by reading DQ7 or

DQ6/DQ2 in the erasing bank. Refer to the “Write

Operation Status” section on page 48 for information

on these status bits.

Once the sector erase operation has begun, only the

Erase Suspend command is valid. All other commands

are ignored. However, note that a hardware reset

immediately terminates the erase operation. If that

occurs, the sector erase command sequence should

be reinitiated once that bank has returned to reading

array data, to ensure data integrity.

The host system may also initiate the sector erase

command sequence while the device is in the unlock

bypass mode. The command sequence is four cycles

cycles in length instead of six cycles. The Unlock

Bypass Reset Command is required to return to

reading array data when the bank is in the unlock

bypass mode.

Figure 5, “Erase Operation,” on page 40 illustrates the

algorithm for the erase operation. Refer to the

Erase/Program Operations table in the Figure , “AC

Characteristics,” on page 69 for parameters and timing

diagrams.

Erase Suspend/Erase Resume Commands

The Erase Suspend command, B0h, allows the system

to interrupt a sector erase operation and then read data

from, or program data to, any sector not selected for

erasure. The bank address is required when writing

this command. This command is valid only during the

sector erase operation, including the minimum tSEA

time-out period during the sector erase command

sequence. The Erase Suspend command is ignored if

written during the chip erase operation or Embedded

Program algorithm.

When the Erase Suspend command is written during

the sector erase operation, the device requires a

maximum of tESL to suspend the erase operation. How-

ever, when the Erase Suspend command is written

during the sector erase time-out, the device immedi-

ately terminates the time-out period and suspends the

erase operation.

After the erase operation has been suspended, the

bank enters the erase-suspend-read mode. The

system can read data from or program data to any

sector not selected for erasure. (The device “erase sus-

pends” all sectors selected for erasure.) Reading at any

address within erase-suspended sectors produces

status information on DQ7–DQ0. The system can use

DQ7, or DQ6 and DQ2 together, to determine if a

sector is actively erasing or is erase-suspended. Refer

to the Figure , “Write Operation Status,” on page 48 for

information on these status bits.

After an erase-suspended program operation is com-

plete, the bank returns to the erase-suspend-read

mode. The system can determine the status of the

program operation using the DQ7 or DQ6 status bits,

just as in the standard program operation. Refer to the

“Write Operation Status” section on page 48 for more

information.

In the erase-suspend-read mode, the system can also

issue the autoselect command sequence. Refer to the

“Autoselect Mode” section on page 14 and “Autoselect

Command Sequence” section on page 36 for details.

To resume the sector erase operation, the system must

write the Erase Resume command. The bank address

of the erase-suspended bank is required when writing

this command. Further writes of the Resume command

BS640HD9V Datasheet(PDF) 41 Page - Advanced Micro Devices

BS640HD9V Datasheet(HTML) 41 Page - Advanced Micro Devices

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

Datasheet Download

Link URL