A29800UM-70 データシートの表示（PDF） - AMIC Technology

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A29800UM-70

1024K X 8 Bit / 512K X 16 Bit CMOS 5.0 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 1) 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.

A29800 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 5. Toggle Bit Algorithm

PRELIMINARY (May, 2001, Version 0.0)

16

AMIC Technology, Inc.

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