A29L004 View Datasheet(PDF) - AMIC Technology

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A29L004

512K X 8 Bit CMOS 3.0 Volt-only, Boot Sector Flash Memory

AMIC Technology 

I/O5: Exceeded Timing Limits

I/O5 indicates whether the program or erase time has

exceeded a specified internal pulse count limit. Under these

conditions I/O5 produces a "1." This is a failure condition

that indicates the program or erase cycle was not

successfully completed.

The I/O5 failure condition may appear if the system tries to

program a "1 "to a location that is previously programmed to

"0." Only an erase operation can change a "0" back to a "1."

Under this condition, the device halts the operation, and

when the operation has exceeded the timing limits, I/O5

produces a "1."

Under both these conditions, the system must issue the

reset command to return the device to reading array data.

I/O3: Sector Erase Timer

After writing a sector erase command sequence, the

system may read I/O3 to determine whether or not an erase

operation has begun. (The sector erase timer does not

apply to the chip erase command.) If additional sectors are

selected for erasure, the entire time-out also applies after

each additional sector erase command. When the time-out

is complete, I/O3 switches from "0" to "1." The system may

ignore I/O3 if the system can guarantee that the time

between additional sector erase commands will always be

less than 50µs. See also the "Sector Erase Command

Sequence" section.

After the sector erase command sequence is written, the

system should read the status on I/O7 ( Data Polling) or

I/O6 (Toggle Bit I) to ensure the device has accepted the

command sequence, and then read I/O3. If I/O3 is "1", the

internally controlled erase cycle has begun; all further

commands (other than Erase Suspend) are ignored until

the erase operation is complete. If I/O3 is "0", the device will

accept additional sector erase commands. To ensure the

command has been accepted, the system software should

check the status of I/O3 prior to and following each

subsequent sector erase command. If I/O3 is high on the

second status check, the last command might not have

been accepted. Table 6 shows the outputs for I/O3.

A29L004 Series

START

Read I/O7-I/O0

Read I/O7-I/O0 (Note 1)

Toggle Bit

No

= Toggle ?

Yes

No

I/O5 = 1?

Yes

Read I/O7 - I/O0

Twice

(Notes 1,2)

Toggle Bit

No

= Toggle ?

Yes

Program/Erase

Operation Not

Commplete, Write

Reset Command

Program/Erase

Operation Complete

Notes :

1. Read toggle bit twice to determine whether or not it is

toggling. See text.

2. Recheck toggle bit because it may stop toggling as I/O5

changes to "1". See text.

Figure 6. Toggle Bit Algorithm

PRELIMINARY (October, 2002, Version 0.0)

18

AMIC Technology, Corp.

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