9
S29C51004T/S29C51004B
V1.0 May 2002
Functional Description
The S29C51004T/S29C51004B consists of 512
equally-sized sectors of 1K bytes each. The 16 KB
lockable Boot Block is intended for storage of the
system BIOS boot code. The boot code is the first
piece of code executed each time the system is
powered on or rebooted.
The S29C51004 is available in two versions: the
S29C51004T with the Boot Block address starting
from 7C000H to 7FFFFH, and the S29C51004B
with the Boot Block address starting from 00000H
to 3FFFFH.
Read Cycle
A read cycle is performed by holding both CE
and OE signals LOW. Data Out becomes valid only
when these conditions are met. During a read cycle
WE must be HIGH prior to CE and OE going LOW.
WE must remain HIGH during the read operation
for the read to complete (see Table 1).
Output Disable
Returning OE or CE HIGH, whichever occurs first
will terminate the read operation and place the l/O
pins in the HIGH-Z state.
Standby
The device will enter standby mode when the CE
signal is HIGH. The l/O pins are placed in the
HIGH-Z, independent of the OE input state.
Byte Write Cycle
The S29C51004T/S29C51004B is programmed
on a byte-by-byte basis. The byte write operation is
initiated by using a specific four-bus-cycle
sequence: two unlock program cycles, a program
setup command and program data program cycles
(see Table 2).
During the byte write cycle, addresses are
latched on the falling edge of either CE or WE,
whichever is last. Data is latched on the rising edge
of CE or WE, whichever is first. The byte write cycle
can be CE controlled or WE controlled.
Sector Erase Cycle
The S29C51004T/S29C51004B features a
sector erase operation which allows each sector to
be erased and reprogrammed without affecting
data stored in other sectors. Sector erase operation
is initiated by using a specific six-bus-cycle
sequence: Two unlock program cycles, a setup
command, two additional unlock program cycles,
and the sector erase command (see Table 2). A
sector must be first erased before it can be re-
written. While in the internal erase mode, the
device ignores any program attempt into the
device. The internal erase completion can be
determined via DATA polling or toggle bit status.
The S29C51004T/S29C51004B is shipped fully
erased (all bits = 1).
16KB Boot Block
1 KB
1 KB
1 KB
1 KB
1 KB
1 KB
16KB Boot Block
S29C51004T
S29C51004B
7FFFFH
7C000H
00000H
03FFFH
51004-15
00000H
16KB Boot Block = 32 Sectors
Table 1. Operation Modes Decoding
NOTES:
1.
X = Don’t Care, VIH = HIGH, VIL = LOW, VH = 12.5V Max.
2.
PD: The data at the byte address to be programmed.
Decoding Mode
CE
OE
WE
A0
A1
A9
I/O
Read
VIL
VIL
VIH
A0
A1
A9
READ
Byte Write
VIL
VIH
VIL
A0
A1
A9
PD
Standby
VIH
X
X
X
X
X
HIGH-Z
Autoselect Device ID
VIL
VIL
VIH
VIH
VIL
VH
CODE
Autoselect Manufacture ID
VIL
VIL
VIH
VIL
VIL
VH
CODE
Enabling Boot Block Protection Lock
VIL
VH
VIL
X
X
VH
X
Disabling Boot Block Protection Lock
VH
VH
VIL
X
X
VH
X
Output Disable
VIL
VIH
VIH
X
X
X
HIGH-Z
SyncMOS Technologies Inc.
S29C51004T/S29C51004B
4 MEGABIT (524,288 x 8 BIT)
5 VOLT CMOS FLASH MEMORY
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