
April 30, 2004 S29GLxxxM_00A5
S29GLxxxM MirrorBit
TM
 Flash Family
115
P r e l i m i n a r y
Write Operation Status
The device provides several bits to determine the status of a program or erase 
operation: DQ2, DQ3, DQ5, DQ6, and DQ7. Table 19 and the following subsec-
tions describe the function of these bits. DQ7 and DQ6 each offer a method for 
determining whether a program or erase operation is complete or in progress. 
The device also provides a hardware-based output signal, RY/BY#, to determine 
whether an Embedded Program or Erase operation is in progress or has been 
completed.
DQ7: Data# Polling
The Data# Polling bit, DQ7, indicates to the host system whether an Embedded 
Program or Erase 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 command sequence.
During the Embedded Program algorithm, the device outputs on DQ7 the com-
plement of the datum programmed to DQ7. This DQ7 status also applies to 
programming during Erase Suspend. When the Embedded Program algorithm is 
complete, the device outputs the datum programmed to DQ7. The system must 
provide the program address to read valid status information on DQ7. If a pro-
gram address falls within a protected sector, Data# Polling on DQ7 is active for 
approximately 1 μs, then the device returns to the read mode. 
During the Embedded Erase algorithm, Data# Polling produces a “0” on DQ7. 
When the Embedded Erase algorithm is complete, or if the device enters the 
Erase Suspend mode, Data# Polling produces a “1” on DQ7. The system must 
provide an address within any of the sectors selected for erasure to read valid 
status information on DQ7.
After an erase command sequence is written, if all sectors selected for erasing 
are protected, Data# Polling on DQ7 is active for approximately 100 μs, then the 
device returns to the read mode. If not all selected sectors are protected, the Em-
bedded Erase algorithm erases the unprotected sectors, and ignores the selected 
sectors that are protected. However, if the system reads DQ7 at an address within 
a protected sector, the status may not be valid.
Just prior to the completion of an Embedded Program or Erase operation, DQ7 
may change asynchronously with DQ0–DQ6 while Output Enable (OE#) is as-
serted low. That is, the device may change from providing status information to 
valid data on DQ7. Depending on when the system samples the DQ7 output, it 
may read the status or valid data. Even if the device has completed the program 
or erase operation and DQ7 has valid data, the data outputs on DQ0–DQ6 may 
be still invalid. Valid data on DQ0–DQ7 will appear on successive read cycles.
Table 
33
 shows the outputs for Data# Polling on DQ7. Figure 7 shows the Data# 
Polling algorithm. Figure 17 in the AC Characteristics section shows the Data# 
Polling timing diagram.