20
MBM29F017A
-70/-90/-12
DQ
2
Toggle Bit II
This toggle bit, along with DQ
6
, can be used to determine whether the device is in the Embedded Erase
TM
Algorithm or in Erase Suspend.
Successive reads from the erasing sector will cause DQ
2
to toggle during the Embedded Erase
TM
Algorithm. If
the device is in the erase-suspended-read mode, successive reads from the erase-suspended sector will cause
DQ
2
to toggle. When the device is in the erase-suspended-program mode, successive reads from the byte
address of the non-erase suspended sector will indicate a logic “1” at the DQ
2
bit.
DQ
6
is different from DQ
2
in that DQ
6
toggles only when the standard program or Erase, or Erase Suspend
Program operation is in progress. The behavior of these two status bits, along with that of DQ
7
, is summarized
as follows:
Notes:
1.These status flags apply when outputs are read from a sector that has been erase-suspended.
2.These status flags apply when outputs are read from the byte address of the non-erase suspended sector.
For example, DQ
2
and DQ
6
can be used together to determine the erase-suspend-read mode. (DQ
2
toggles
while DQ
6
does not.) See also Table 7 and Figure 14.
Furthermore, DQ
2
can also be used to determine which sector is being erased. When the device is in the erase
mode, DQ
2
toggles if this bit is read from the erasing sector.
RY/BY
Ready/Busy
The MBM29F017A provides a RY/BY open-drain output pin as a way to indicate to the host system that the
Embedded Algorithms are either in progress or has been completed. If the output is low, the device is busy with
either a program or erase operation. If the output is high, the device is ready to accept any read/write or erase
operation. When the RY/BY pin is low, the device will not accept any additional program or erase commands
with the exception of the Erase Suspend command. If the MBM29F017A is placed in an Erase Suspend mode,
the RY/BY output will be high, by means of connecting with a pull-up resistor to V
CC
.
During programming, the RY/BY pin is driven low after the rising edge of the fourth WE pulse. During an erase
operation, the RY/BY pin is driven low after the rising edge of the sixth WE pulse. The RY/BY pin will indicate a
busy condition during RESET pulse. Refer to Figure 10 for a detailed timing diagram. The RY/BY pin is pulled
high in standby mode.
Since this is an open-drain output, several RY/BY pins can be tied together in parallel with a pull-up resistor to V
CC
.
Mode
DQ
7
DQ
6
DQ
2
Program
DQ
7
toggles
1
Erase
0
toggles
toggles
Erase Suspend Read (1)
(Erase-Suspended Sector)
1
1
toggles
Erase Suspend Program
DQ
7
(2)
toggles
1 (2)