MBM29LV017 Ver la hoja de datos (PDF) - Fujitsu

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MBM29LV017

CMOS 16M (2M × 8) BIT

Fujitsu 

MBM29LV017-80/-90/-12

DQ7

Data Polling

The MBM29LV017 device features Data Polling as a method to indicate to the host that the Embedded Algorithms

are in progress or completed. During the Embedded Program Algorithm, an attempt to read the device will

produce the complement of the data last written to DQ7. Upon completion of the Embedded Program Algorithm,

an attempt to read the device will produce the true data last written to DQ7. During the Embedded Erase Algorithm,

an attempt to read the device will produce a “0” at the DQ7 output. Upon completion of the Embedded Erase

Algorithm an attempt to read the device will produce a “1” at the DQ7 output. The flowchart for Data Polling (DQ7)

is shown in Figure 19.

For chip erase and sector erase, the Data Polling is valid after the rising edge of the sixth WE pulse in the six

write pulse sequence. Data Polling must be performed at sector address within any of the sectors being erased

and not a protected sector. Otherwise, the status may not be valid. Once the Embedded Algorithm operation is

close to being completed, the MBM29LV017 data pins (DQ7) may change asynchronously while the output enable

(OE) is asserted low. This means that the device is driving status information on DQ7 at one instant of time and

then that byte’s valid data at the next instant of time. Depending on when the system samples the DQ7 output,

it may read the status or valid data. Even if the device has completed the Embedded Algorithm operation and

DQ7 has a valid data, the data outputs on DQ0 to DQ6 may be still invalid. The valid data on DQ0 to DQ7 will be

read on the successive read attempts.

The Data Polling feature is only active during the Embedded Programming Algorithm, Embedded Erase

Algorithm, or sector erase time-out. (See Table 8.)

See Figure 9 for the Data Polling timing specifications and diagrams.

DQ6

Toggle Bit I

The MBM29LV017 also features the “Toggle Bit I” as a method to indicate to the host system that the Embedded

Algorithms are in progress or completed.

During an Embedded Program or Erase Algorithm cycle, successive attempts to read (OE toggling) data from

the devices will result in DQ6 toggling between one and zero. Once the Embedded Program or Erase Algorithm

cycle is completed, DQ6 will stop toggling and valid data will be read on the next successive attempts. During

programming, the Toggle Bit I is valid after the rising edge of the fourth WE pulse in the four write pulse sequence.

For chip erase and sector erase, the Toggle Bit I is valid after the rising edge of the sixth WE pulse in the six

write pulse sequence. The Toggle Bit I is active during the sector time out.

In programming, if the sector being written to is protected, the toggle bit will toggle for about 2 µs and then stop

toggling without the data having changed. In erase, the device will erase all the selected sectors except for the

ones that are protected. If all selected sectors are protected, the chip will toggle the toggle bit for about 50 µs

and then drop back into read mode, having changed none of the data.

Either CE or OE toggling will cause the DQ6 to toggle. In addition, an Erase Suspend/Resume command will

cause the DQ6 to toggle.

See Figure 10 and Figure 20 for the Toggle Bit I timing specifications and diagrams.

20

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