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A28F200BR
10
ADVANCE INFORMATION
2.1.2
TWO 8-KB PARAMETER BLOCKS
The boot block architecture includes parameter
blocks to facilitate storage of frequently updated
small parameters that would normally require an
EEPROM. By using software techniques, the byte-
rewrite functionality of EEPROMs can be emulated.
These techniques are detailed in Intel’s AP-604,
“Using Intel’s Boot Block Flash Memory Parameter
Blocks to Replace EEPROM.” Each boot block
component contains two parameter blocks of eight
Kbytes (8,192 bytes) each. The parameter blocks
are not write-protectable.
2.1.3
ONE 96-KB + THREE 128-KB MAIN
BLOCKS
After the allocation of address space to the boot
and parameter blocks, the remainder is divided into
main blocks for data or code storage. Each 2-Mbit
device contains one 96-Kbyte (98,304 byte) block
and one 128-Kbyte (131,072 byte) block. See the
memory maps for each device for more information.
3.0
PRODUCT FAMILY PRINCIPLES
OF OPERATION
Flash memory augments EPROM functionality with
in-circuit electrical program and erase. The boot
block flash family utilizes a Command User
Interface (CUI and automated algorithms to simplify
program and erase operations. The CUI allows for
100% TTL-level control inputs, fixed power supplies
during erasure and programming, and maximum
EPROM compatibility.
When V
PP
< V
PPLK
, the device will only successfully
execute the following commands: Read Array,
Read Status Register, Clear Status Register and
intelligent identifier mode. The device provides
standard EPROM read, standby and output disable
operations. Manufacturer identification and device
Identification data can be accessed through the CUI
or through the standard EPROM A
9
high voltage
access (V
ID
) for PROM programming equipment.
The same EPROM read, standby and output
disable functions are available when 5V or 12V is
applied to the V
PP
pin. In addition, 5V or 12V on
V
PP
allows program and erase of the device. All
functions associated with altering memory contents:
Program and Erase, Intelligent Identifier Read, and
Read Status are accessed via the CUI.
The purpose of the Write State Machine (WSM) is
to completely automate the programming and
erasure of the device. The WSM will begin
operation upon receipt of a signal from the CUI and
will report status back through a Status Register.
The CUI will handle the WE# interface to the data
and address latches, as well as system software
requests for status while the WSM is in operation.
28F200-B
128-Kbyte MAIN BLOCK
8-Kbyte PARAMETER BLOCK
16-Kbyte BOOT BLOCK
8-Kbyte PARAMETER BLOCK
96-Kbyte MAIN BLOCK
00000H
10000H
1BFFFH
1C000H
1D000H
1E000H
1FFFFH
28F200-T
128-Kbyte MAIN BLOCK
8-Kbyte PARAMETER BLOCK
16-Kbyte BOOT BLOCK
8-Kbyte PARAMETER BLOCK
96-Kbyte MAIN BLOCK
1FFFFH
10000H
04000H
03FFFH
03000H
02000H
00000H
0542-03
Figure 3. 28F200-T/B Memory Maps