Advance Information
32 Mbit Concurrent SuperFlash + 4/8 Mbit SRAM ComboMemory
SST34HF3242C / SST34HF3244C
SST34HF3282 / SST34HF3284
3
©2005 Silicon Storage Technology, Inc. S71282-00-000 8/05
Flash Program Operation
These devices are programmed on a word-by-word or
byt e-by-byte basis depen ding on the stat e of the CI OF pin.
Before programming, one must ensure that the sector
being prog rammed is fully er ased.
The Progr am operat ion is accomplished in t hree steps:
1. Software Data Protection is initiated using the
three-byte load sequence.
2. Address and data are loaded.
During the Program operation, the addresses are
latched on the falling edge of either BEF# or WE#,
whichever occurs last. The data is latched on the
rising edge of either BEF# or WE#, whichever
occurs first.
3. The internal Program operation is initiated after
the rising edge of the fourth WE# or BEF#, which-
ever occurs first. The Program operation, once ini-
tiated, will be completed typically within 7 µs.
See Figures 7 and 8 for WE# and BEF# controlled Pro-
gram operation timing diagrams and Figure 21 for flow-
char ts. During the Program operation, the only valid reads
are Data# Polling and Toggle Bit. During the internal Pro-
gram o peration, the host is free to perform additional tasks.
Any commands issued during an internal Program opera-
tion are ignored.
Flash Sector- /Block-Erase Operation
These devices offer both Sector-Erase and Block-Erase
operatio ns. These operations allo w the system to erase th e
devices on a sector-by-sector (or block-by-block) basis.
The sector architectu re is based on a uniform sector siz e of
2 KWord. The Block-Erase mode is based on a uniform
bl ock siz e of 32 KW ord. The Sector-Erase oper ation is initi-
ated by executing a six-byte command sequence with a
Sector-Erase command (50H) and sector address (SA) in
the last b us cycle . The Bloc k-Er ase oper ation is init iated b y
executing a six-byte command sequence with Block-Erase
command (30H) and block address (BA) in the last bus
cycle. The sector or block address is latched on the falling
edge of the sixth WE# pu lse, while the command (30H or
50H) is latched on the rising edge of the sixth WE# pulse.
The internal Erase operation begins after the sixth WE#
pulse. Any commands issued dur ing the Block- or Sector-
Erase operation are ignored except Erase-Suspend and
Erase-Resume. See Figures 12 and 13 for timing wave-
forms.
Flash Chip-Erase Operation
The SST34HF32x2xC/32x4x provide a Chip-Erase opera-
tion, which allows the user to erase all flash sectors/blocks
to the “1” state. This is useful when the device must be
quickly er ased.
The Chip-Erase operation is initiated by executing a six-
byte command sequence with Chip-Er ase command (10H)
at address 555H in the last byte sequence. The Erase
operation begins with the rising edge of the sixth WE# or
BEF#, whichever occurs first. Dur ing the Erase operation,
the only valid read is Toggle Bits or Data# Polling. See
Table 6 for the command sequence, Figure 11 for timing
diagram, and Figure 25 for the flowchart. Any commands
issued during the Chip-Erase oper at ion are ignored. When
WP# is low, any attempt to Chip-Erase will be ignored.
Flash Erase-Suspend/-Resume Operations
The Erase-Suspend operation temporarily suspends a
Sector- or Block-Erase operation thus allowing data to be
read from any memor y location, or program data into any
sector/block that is not suspended for an Erase operation.
The operat ion is ex ecuted by issuing a one-b yte comman d
sequence with Erase-Suspend command (B0H). The
de vice automatically enters read mode no more than 10 µs
after the Erase-Suspend command had been issued. (TES
maximum latency equals 10 µs.) Valid data can be read
from any sector or block that is not suspended from an
Erase opera tion. Reading at address locatio n within erase -
suspended sectors/blocks will output DQ2 toggling and
DQ6 at “1”. While in Erase-Suspend mode, a Program
operation is allowed except for the sector or block selected
for Erase-Suspend. To resume Sector-Erase or Block-
Erase operation which has been suspended, the system
must issue an Erase-Resume command. The operat ion is
executed by issuing a one-byte command sequence with
Erase Resume command (30H) at any address in the one-
byt e sequence.