Numonyx™ StrataFlash® Cellular Memory (M18)
9.5.1
Control Mode
Control Mode programming is invoked when only the A-half (A3 = 0) of the
programming region is programmed to 0s, as shown in Figure 47, “Configurable
Programming Regions: Control Mode and Object Mode” on page 85. The B-half (A3 =
1) remains erased. Control mode allows up to 512 bytes of data to be programmed in
the region. The information can be programmed in bits, bytes, or words.
Control Mode supports the following programming methods:
— Single-word Programming (0041h)
— Buffered Programming (00E9h/00D0h), and
— Buffered Enhanced Factory Programming (0080h/00D0h)
When buffered programming is used in Control Mode, all addresses must be in the A-
half of the buffer (A3 = 0). During buffer fill, the B-half (A3 = 1) addresses do not need
to be filled with 0xFFFF.
Control Mode programming is useful for storing dynamic information, such as FFS
Headers, File Info, and so on. Typically, Control Mode programming does not require
the entire 512 bytes of data to be programmed at once. It may also contain data that is
changed after initial programming using a technique known as “bit twiddling”. Header
information can be augmented later with additional new information within a Control
Mode-programmed region. This allows implementation of legacy file systems, as well as
transaction-based power-loss recovery.
In a control mode region, programming operations can be performed multiple times.
However, care must be taken to avoid programming any zero’s in the B-half (A3 = 1) of
the region. Violation of this usage will cause SR4 and SR9 to be set, and the program
operation will be aborted. See Table 38, “Programming Region Next State Table” on
page 88 for details.
Datasheet
84
April 2008
309823-10
NUMONYX [ NUMONYX B.V ]
