m28f410 STMicroelectronics, m28f410 Datasheet - Page 26

• Manufacturer Part Number: m28f410
• Description: 4 Megabit X8 Or X16, Block Erase Flash Memory
• Manufacturer: STMicroelectronics

Figure 10. Memory Map, Word-wide Addresses
Memory Blocks
The memory blocks of the M28F410 and M28F420
are shown in Figure 10. The differencebetween the
two productsis simply an inversion of the block map
to position the Boot Block at the top or bottom of
the memory. The selection of the Boot Block at the
top or bottom of the memory depends on the
microprocessor needs.
Each block of the memory can be erased sepa-
rately, but only by one block at a time. The erase
operation is managed by the P/E.C. but can be
suspended in order to read from another block and
then resumed.
Programming and erasure of the memory is dis-
abled when the program supply is at V
successful programming and erasure the program
supply must be at V
The Boot Block provides additional hardware secu-
rity by use of the RP signal which must be at V
before any program or erase operation will be
executed by the P/E.C. on the Boot Block.
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3DFFFh
3CFFFh
3BFFFh
3FFFFh
2FFFFh
1FFFFh
0FFFFh
3E000h
3D000h
3C000h
A0-A17
30000h
20000h
10000h
00000h
M28F410 TOP BOOT BLOCK
PPH
.
4K PARAMETER BLOCK
4K PARAMETER BLOCK
48K MAIN BLOCK
64K MAIN BLOCK
64K MAIN BLOCK
64K MAIN BLOCK
8K BOOT BLOCK
Word Wide
PPL
. For
HH
Operations
Operations are defined as specific bus cycles and
signals which allow memory Read, Command
Write, Output Disable, Standby, Power Down, and
Electronic Signature Read. They are shown in Ta-
ble 3.
Read. Read operations are used to output the
contents of the Memory Array, the Status Register
or the Electronic Signature. Both Chip Enable E
and Output Enable G must be low in order to read
the output of the memory. The Chip Enable input
also provides power control and should be used for
device selection. Output Enable should be used to
gate data onto the output independentof the device
selection. A read operation will output either a byte
or a word depending on the BYTE signal level.
WhenBYTE is Low the output byte is on DQ0-DQ7,
DQ8-DQ14 are Hi-Z and A-1 is an additional ad-
dress input. When BYTE is High the output word is
on DQ0-DQ15.
The data read depends on the previous command
written to the memory (see instructions RD, RSR
and RSIG).
3FFFFh
2FFFFh
1FFFFh
0FFFFh
03FFFh
02FFFh
01FFFh
A0-A17
30000h
20000h
10000h
04000h
03000h
02000h
00000h
M28F420 BOTTOM BOOT BLOCK
4K PARAMETER BLOCK
4K PARAMETER BLOCK
64K MAIN BLOCK
64K MAIN BLOCK
64K MAIN BLOCK
48K MAIN BLOCK
8K BOOT BLOCK
Word Wide
AI01277