M28F410 View Datasheet(PDF) - STMicroelectronics
Part Name
Description
MFG CO.
'M28F410' PDF : 38 Pages View PDF
M28F410, M28F420
Figure 10. Memory Map, Word-wide Addresses
M28F410 TOP BOOT BLOCK
A0-A17
3FFFFh
3E000h
3DFFFh
3D000h
3CFFFh
3C000h
3BFFFh
30000h
2FFFFh
20000h
1FFFFh
10000h
0FFFFh
00000h
Word Wide
8K BOOT BLOCK
4K PARAMETER BLOCK
4K PARAMETER BLOCK
48K MAIN BLOCK
64K MAIN BLOCK
64K MAIN BLOCK
64K MAIN BLOCK
M28F420 BOTTOM BOOT BLOCK
A0-A17
3FFFFh
30000h
2FFFFh
20000h
1FFFFh
10000h
0FFFFh
04000h
03FFFh
03000h
02FFFh
02000h
01FFFh
00000h
Word Wide
64K MAIN BLOCK
64K MAIN BLOCK
64K MAIN BLOCK
48K MAIN BLOCK
4K PARAMETER BLOCK
4K PARAMETER BLOCK
8K BOOT BLOCK
AI01277
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 VPPL. For
successful programming and erasure the program
supply must be at VPPH.
The Boot Block provides additional hardware secu-
rity by use of the RP signal which must be at VHH
before any program or erase operation will be
executed by the P/E.C. on the Boot Block.
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).
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