s29cd-j Meet Spansion Inc., s29cd-j Datasheet - Page 34

• Manufacturer Part Number: s29cd-j
• Description: 32/16 Megabit Cmos 2.6 Volt Or 3.3 Volt-only Simultaneous Read/write, Dual Boot, Burst Mode Flash Memory With Versatilei/o?
• Manufacturer: Meet Spansion Inc.

8.8
34
8.7.8
8.8.1
Write Operation Status
Simultaneous Read/Write
DQ7: Data# Polling
During the unlock bypass mode only the Read, Unlock Bypass Program and Unlock Bypass Reset
commands are valid. To exit the unlock bypass mode, the system must issue the two-cycle unlock bypass
reset command sequence, which returns the device to read mode.
Notes
The simultaneous read/write feature allows the host system to read data from one bank of memory while
programming or erasing in another bank of memory.
The Simultaneous Read/Write feature can be used to perform the following:
The Simultaneous R/W feature can not be performed during the following modes:
As an alternative to using the Simultaneous Read/Write feature, the user may also suspend an erase or
program operation to read in another location within the same bank (except for the sector being erased).
The device provides several bits to determine the status of a program or erase operation. The following
subsections describe the function of DQ7, DQ6, DQ2, DQ5, DQ3, and RY/BY#.
The Data# Polling bit, DQ7, indicates to the host system whether an Embedded Program or Erase algorithm
is in progress or completed, or whether a bank is in Erase Suspend. Data# Polling is valid after the rising
edge of the final WE# pulse in the command sequence. Note that Data# Polling returns invalid data for the
address being programmed or erased.
During the Embedded Program algorithm, the device outputs on DQ7 the complement 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 program address falls within a protected sector, Data# polling on DQ7 is active for approximately 1 µs,
then that bank returns to the read mode without programming the sector. If an erase address falls within a
protected sector, Toggle BIT (DQ6) is active for 150 s, then the device returns to the read mode without
erasing the sector. Please note that Data# polling (DQ7) may give misleading status when an attempt is
made to program or erase a protected sector.
During the Embedded Erase Algorithm, Data# polling produces a “0” on DQ7. When the Embedded Erase
algorithm is complete 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.
In asynchronous mode, just prior to the completion of an Embedded Program or Erase operation, DQ7 may
change asynchronously with DQ6-DQ0 while Output Enable (OE#) is asserted 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
Programming in one bank, while reading in the other bank
Erasing in one bank, while reading in the other bank
Programming a PPB, while reading data from the large bank or status from the small bank
Erasing a PPB, while reading data from the large bank or status from the small bank
Any of the above situations while in the Secured Silicon Sector Mode
CFI Mode
Password Program operation
Password Verify operation
1. The Unlock Bypass Command is ignored if the Secured Silicon sector is enabled.
2. Unlike the standard program or erase commands, there is no Unlock Bypass Program/Erase
Suspend or Program/Erase Resume command.
S29CD-J & S29CL-J Flash Family
D a t a
S h e e t
( P r e l i m i n a r y )
S29CD-J_CL-J_00_B2 March 7, 2007