FLASH

AS8FLC2M32

AS8FLC2M32B

Rev. 1.6 05/11

Micross Components reserves the right to change products or specifications without notice.

14

DQ7, DQ15, DQ23 and DQ31 may change asynchronously

with the 7 lower order bits within each Byte, while the OEx\

pins are asserted Low.

DQ6, DQ14, DQ22 and DQ30: Toggle Bit 1

Toggle Bit 1 indicates whether an Embedded Program or Erase

Algorithm is in progress, complete, or has entered the ERASE

SUSPEND mode. Toggle Bit 1 may be read at any address

and is valid after the rising edge of the final WEx\ pulse in

the command sequence as well as during the sector ERASE

time-out.

During an Embedded Program or Erase Algorithm operation,

successive READ cycles that access any address will cause this

status indicator to toggle. When the operation is complete, the

status bit will stop toggling.

After an ERASE command sequence is WRITTEN, if all

sectors selected for ERASING are protected, the toggle bit(s)

will toggle for approximately 100uS, then will become steady

state as the device returns to READING array data. If not all

selected sectors are protected, the Embedded Erase Algorithm

will cause ERASURE of unprotected sectors, ignoring the

selected sectors that are protected.

The System can use DQ2, DQ6 of Byte 1; DQ10, DQ14 of Byte

2; DQ18, DQ22 of Byte 3; DQ26, DQ30 of Byte 4 together to

determine whether a sector is actively ERASING or is ERASE

SUSPENDED. When the device is actively ERASING the DQ6

of Byte 1; DQ14 of Byte 2; DQ22 of Byte 3 and DQ30 of Byte

4 toggles and when the devices enters ERASE SUSPEND, the

status bit returns to a steady state. However, the system must

also use DQ2 of Byte 1; DQ10 of Byte 2, DQ18 of Byte 3 and

DQ26 of Byte 4 to determine which sectors are ERASING or

ERASE SUSPENDED in each of the Bytes contained in the

Module. Alternatively DQ7, DQ15, DQ23 and DQ31 can be

used (see DQ7, DQ15, DQ23, DQ31 Data\ Polling).

If a program address falls within a protected sector, DQ6, 14,

22, and or DQ30 will toggle for approximately 1us after the

PROGRAM command sequence is WRITTEN, then returns to

READING Array data.

DQ6, 14, 22, and or DQ30 also toggles during the ERASE

SUSPEND program mode, stops toggling once the operation

is complete.

DQ2, DQ10, DQ18 and DQ26: Toggle Bit II

The “Toggle Bit II” on each of the Bytes, when used with

DQ6, 14, 22, and DQ30 indicates whether a particular sector

is actively ERASING or whether that sector is ERASE-

SUSPENDED. Toggle Bit II is valid after the rising edge of

the final WEx\ pulse in the command sequence.

DQ2, 10, 18 and or DQ26 toggles when the system READS

at addresses within those sectors that have been selected for

ERASURE, but does not indicate when a sector is being

ERASED. DQ6, 14, 22 and DQ30 by comparison indicates

that a device is actively ERASING or in ERASE SUSPEND,

but cannot distinguish which sectors are selected for the

operation, therefore both status bits are required for sector and

mode information.

Reading Toggle Bits I/II

Whenever the system initially begins READING toggle bit

statuses, it must READ Byte data (ie…DQ0-7, DQ8-15,

DQ16-23 and or DQ24-31) at least twice in a row to determine

whether a Toggle Bit is toggling. Typically, the system would

note and store the value of the toggle bit after the first READ.

After the second READ, the system would compare the new

value of the Toggle Bit with the first. If the toggle bit is not

toggling the device has completed the PROGRAM or ERASE

operation. The system can READ array data on each Byte

during the next READ cycle.

If after the initial two READ cycles, the system determines

that the toggle bit is still toggling, the system also should note

whether the value of DQ5, 13, 21 and or DQ29 is High. If

High, the system should then determine again whether the

toggle bit(s) are again toggling, since the toggle bit may have

indeed stop toggling just as DQ5, 13, 21 and or DQ29 went

High. If the toggle bit is no longer toggling, the device has

successfully completed the operation. If the toggle bit is still

active (toggling), the device has not successfully completed the

operation and the system must WRITE the RESET command

to return to READING array data.