m29f040 STMicroelectronics, m29f040 Datasheet - Page 7

• Manufacturer Part Number: m29f040
• Description: 4 Mbit 512kb X8, Uniform Block Single Supply Flash Memory
• Manufacturer: STMicroelectronics

Figure 3. Memory Map and Block Address Table
Instructions and Commands
The Command Interface (C.I.) latches commands
written to the memory. Instructions are made up
from one or more commands to perform Read
Array/Reset, Read Electronic Signature, Block
Erase, Chip Erase, Program, Block Erase Suspend
and Erase Resume. Commands are made of ad-
dress and data sequences. Addresses are latched
on the falling edge of W or E and data is latched
on the rising of W or E. The instructions require from
1 to 6 cycles, the first or first three of which are
always write operations used to initiate the com-
mand. They are followed by either further write
cycles to confirm the first command or execute the
command immediately. Command sequencing
must be followed exactly. Any invalid combination
of commands will reset the device to Read Array.
The increased number of cycles has been chosen
to assure maximum data security. Commands are
initialised by two preceding coded cycles which
unlock the Command Interface. In addition, for
Erase, command confirmation is again preceeded
by the two coded cycles.
P/E.C. status is indicated during command execu-
tion by Data Polling on DQ7, detection of Toggle on
AI01362B
A18
1
1
1
1
0
0
0
0
A17
1
1
0
0
1
1
0
0
A16
1
0
1
0
1
0
1
0
64K Bytes Block
64K Bytes Block
64K Bytes Block
64K Bytes Block
64K Bytes Block
Table 7. Commands
DQ6, or Error on DQ5 and Erase Timer DQ3 bits.
Any read attempt during Program or Erase com-
mand execution will automatically output those four
bits. The P/E.C. automatically sets bits DQ3, DQ5,
DQ6 and DQ7. Other bits (DQ0, DQ1, DQ2 and
DQ4) are reserved for future use and should be
masked.
Hex Code
00h
10h
30h
80h
90h
A0h
B0h
F0h
ADDRESS
Read
Chip Erase Confirm
Block Erase Resume/Confirm
Set-up Erase
Read Electronic Signature/
Block Protection Status
Program
Erase Suspend
Read Array/Reset
7FFFFh
6FFFFh
5FFFFh
4FFFFh
3FFFFh
2FFFFh
1FFFFh
0FFFFh
TOP
ADDRESS
BOTTOM
Command
70000h
60000h
50000h
40000h
30000h
20000h
10000h
00000h
M29F040
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