Numonyx™ Wireless Flash Memory (W18)
• CFI Query: Returns Common Flash Interface (CFI) information. CFI information
can be accessed starting at 4-Mbit partition base addresses.
• Read Status Register: Returns Status Register (SR) data from the addressed
partition.
The appropriate CUI command must be written to the partition in order to place it in
the desired read state (see Table 22, “Command Codes and Descriptions” on page 51).
Non-array read operations (Read ID, CFI Query, and Read Status Register) execute as
single synchronous or asynchronous read cycles. WAIT is asserted throughout non-
array read operations.
9.1.2
Writes
Device write operations are performed by placing the desired address on A[22:0] and
asserting CE# and WE#. OE# and RST# must be high. Data to be written at the
desired address is placed on DQ[15:0]. ADV# must be held low throughout the write
cycle or it can be toggled to latch the address. If ADV# is held low, the address and
data are latched on the rising edge of WE#. CLK is not used during write operations,
and is ignored; it can be either free-running or halted at VIL or VIH. All write operations
are asynchronous.
Table 22, “Command Codes and Descriptions” on page 51 shows the available device
commands. Appendix A, “Write State Machine States” on page 86 provides information
on moving between different device operations by using CUI commands.
9.1.3
9.1.4
Output Disable
When OE# is deasserted, device outputs DQ[15:0] are disabled and placed in a high-
impedance (High-Z) state.
Burst Suspend
The Burst Suspend feature allows the system to temporarily suspend a synchronous-
burst read operation. This can be useful if the system needs to access another device
on the same address and data bus as the flash during a burst-read operation.
Synchronous-burst accesses can be suspended during the initial latency (before data is
received) or after the device has output data. When a burst access is suspended,
internal array sensing continues and any previously latched internal data is retained.
Burst Suspend occurs when CE# is asserted, the current address has been latched
(either ADV# rising edge or valid CLK edge), CLK is halted, and OE# is deasserted. CLK
can be halted when it is at VIH or VIL. To resume the burst access, OE# is reasserted
and CLK is restarted. Subsequent CLK edges resume the burst sequence where it left
off.
Within the device, CE# gates WAIT. Therefore, during Burst Suspend WAIT is still
driven. This can cause contention with another device attempting to control the
system’s READY signal during a Burst Suspend. Systems using the Burst Suspend
feature should not connect the device’s WAIT signal directly to the system’s READY
signal. Refer to Figure 13, “Burst Suspend” on page 36.
November 2007
Order Number: 290701-18
Datasheet
49
NUMONYX [ NUMONYX B.V ]
