This Data Sheet may be revised by subsequent versions

©2003 Eon Silicon Solution, Inc., www.essi.com.tw

or modifications due to changes in technical specifications.

11

EN29F040A

Rev. B, Issue Date: 2004/04/01

WRITE OPERATION STATUS

DQ7

DATA Polling

The EN29F040A provides DATA Polling on DQ7 to indicate to the host system the status of the

embedded operations. The DATA Polling feature is active during the Byte Programming, Sector

Erase, Chip Erase, and Erase Suspend. (See Table 6)

When the Byte Programming is in progress, an attempt to read the device will produce the

complement of the data last written to DQ7. Upon the completion of the Byte Programming, an

attempt to read the device will produce the true data last written to DQ7. For the Byte Programming,

When the embedded Erase is in progress, an attempt to read the device will produce a “0” at the

DQ7 output. Upon the completion of the embedded Erase, the device will produce the “1” at the DQ7

output during the read. For Chip Erase, the DATA polling is valid after the rising edge of the sixth

WE or

rising edge of the sector erase WE or CE pulse.

address used is in a protected sector.

Just prior to the completion of the embedded operations, DQ7 may change asynchronously when

one instant of time and valid data at the next instant of time.

Depending on when the system

samples the DQ7 output, it may read the status of valid data. Even if the device has completed the

embedded operations and DQ7 has a valid data, the data output on DQ0-DQ6 may be still invalid.

The valid data on DQ0-DQ7 will be read on the subsequent read attempts.

The flowchart for DATA Polling (DQ7) is shown on Flowchart 5. The DATA Polling (DQ7) timing

diagram is shown in Figure 8.

DQ6

Toggle Bit I

The EN29F040A provides a “Toggle Bit” on DQ6 to indicate to the host system the status of the

embedded programming and erase operations. (See Table 6)

During an embedded Program or Erase operation, successive attempts to read data from the device

at any address (by toggling OE or CE ) will result in DQ6 toggling between “zero” and “one”. Once

the embedded Program or Erase operation is complete, DQ6 will stop toggling and valid data will be

read on the next successive attempts. During Byte Programming, the Toggle Bit is valid after the

rising edge of the fourth WE pulse in the four-cycle sequence. For Chip Erase, the Toggle Bit is

valid after the rising edge of the sixth-cycle sequence. For Sector Erase, the Toggle Bit is valid after

erase time-out window.