A29400 Series
Write Operation Status
Several bits, I/O2, I/O3, I/O5, I/O6, I/O7, RY/
are
START
BY
provided in the A29400 to determine the status of a write
operation. Table 6 and the following subsections describe
the functions of these status bits. I/O7, I/O6 and RY/
BY
each offer a method for determining whether a program or
erase operation is complete or in progress. These three
bits are discussed first.
Read I/O7-I/O0
Address = VA
I/O7:
Polling
Data
The
Polling bit, I/O7, indicates to the host system
Data
Yes
whether an Embedded Algorithm is in progress or
completed, or whether the device is in Erase Suspend.
I/O7 = Data ?
No
Polling is valid after the rising edge of the final
WE
Data
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.
No
I/O5 = 1?
Yes
If a program address falls within a protected sector,
Data
Polling on I/O7 is active for approximately 2ms, then the
device returns to reading array data.
Read I/O7 - I/O0
Address = VA
During the Embedded Erase algorithm,
Polling
Data
produces a "0" on I/O7. When the Embedded Erase
algorithm is complete, or if the device enters the Erase
Suspend mode,
Polling produces a "1" on I/O7.This
Data
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.
Yes
I/O7 = Data ?
No
After an erase command sequence is written, if all sectors
selected for erasing are protected,
Polling on I/O7 is
Data
active for approximately 100ms, 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
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/O 5 = "1" because
I/O7 may change simultaneously with I/O 5.
Enable (
) is asserted low. The
Polling Timings
Data
OE
(During Embedded Algorithms) figure in the "AC
Characteristics" section illustrates this. Table 6 shows the
Figure 4. Data Polling Algorithm
outputs for
Polling on I/O7. Figure 4 shows the
Data
Polling algorithm.
Data
PRELIMINARY
(February, 2001, Version 0.1)
13
AMIC Technology, Inc.