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A29040V

512K X 8 Bit CMOS 5.0 Volt-only, Uniform Sector Flash Memory

AMIC Technology 

Write Operation Status

Several bits, I/O2, I/O3, I/O5, I/O6, and I/O7, are provided in

the A29040 to determine the status of a write operation.

Table 5 and the following subsections describe the

functions of these status bits. I/O7, I/O6 and I/O2 each offer

a method for determining whether a program or erase

operation is complete or in progress. These three bits are

discussed first.

I/O7: Data Polling

The Data Polling bit, I/O7, indicates to the host system

whether an Embedded Algorithm is in progress or

completed, or whether the device is in Erase Suspend.

Data Polling is valid after the rising edge of the final WE

pulse in the program or erase command sequence.

During the Embedded Program algorithm, the device

outputs on I/O7 the complement of the datum programmed

to I/O7. This I/O7 status also applies to programming during

Erase Suspend. When the Embedded Program algorithm is

complete, the device outputs the datum programmed to

I/O7. The system must provide the program address to read

valid status information on I/O7. If a program address falls

within a protected sector, Data Polling on I/O7 is active for

approximately 2µs, then the device returns to reading array

data.

During the Embedded Erase algorithm, Data Polling

produces a "0" on I/O7. When the Embedded Erase

algorithm is complete, or if the device enters the Erase

Suspend mode, Data Polling produces a "1" on I/O7.This is

analogous to the complement/true datum output described

for the Embedded Program algorithm: the erase function

changes all the bits in a sector to "1"; prior to this, the

device outputs the "complement," or "0." The system must

provide an address within any of the sectors selected for

erasure to read valid status information on I/O7.

After an erase command sequence is written, if all sectors

selected for erasing are protected, Data Polling on I/O7 is

active for approximately 100µs, then the device returns to

reading array data. If not all selected sectors are protected,

the Embedded Erase algorithm erases the unprotected

sectors, and ignores the selected sectors that are

protected.

When the system detects I/O7 has changed from the

complement to true data, it can read valid data at I/O7 - I/O0

on the following read cycles. This is because I/O7 may

change asynchronously with I/O0 - I/O6 while Output Enable

( OE ) is asserted low. The Data Polling Timings (During

Embedded Algorithms) figure in the "AC Characteristics"

section illustrates this. Table 5 shows the outputs for Data

Polling on I/O7. Figure 3 shows the Data Polling algorithm.

A29040 Series

START

Read I/O7-I/O0

Address = VA

Yes

I/O7 = Data ?

No

No

I/O5 = 1?

Yes

Read I/O7 - I/O0

Address = VA

Yes

I/O7 = Data ?

No

FAIL

PASS

Note :

1. VA = Valid address for programming. During a sector

erase operation, a valid address is an address within any

sector selected for erasure. During chip erase, a valid

address is any non-protected sector address.

2. I/O7 should be rechecked even if I/O5 = "1" because

I/O7 may change simultaneously with I/O5.

Figure 3. Data Polling Algorithm

PRELIMINARY (August, 2001, Version 0.5)

11

AMIC Technology, Inc.

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