256Mb: 3V Embedded Parallel NOR Flash
Memory Organization
Table 2: Signal Descriptions (Continued)
Name
Type
Description
VCC
Supply
Supply voltage: Provides the power supply for READ, PROGRAM, and ERASE operations.
The command interface is disabled when VCC ≤ VLKO. This prevents WRITE operations from ac-
cidentally damaging the data during power-up, power-down, and power surges. If the pro-
gram/erase controller is programming or erasing during this time, then the operation aborts,
and the contents being altered will be invalid.
A 0.1μF capacitor should be connected between VCC and VSS to decouple the current surges
from the power supply. The PCB track widths must be sufficient to carry the currents required
during PROGRAM and ERASE operations. (See DC Characteristics.)
VCCQ
Supply
I/O supply voltage: Provides the power supply to the I/O pins and enables all outputs to be
powered independently from VCC
.
VSS
Supply
–
Ground: All VSS pins must be connected to the system ground.
Reserved for future use: RFUs should be not connected.
RFU
Memory Organization
Memory Configuration
The main memory array is divided into 128KB or 64KW uniform blocks.
Memory Map – 256Mb Density
Table 3: 256Mb, Blocks[255:0]
Address Range (x8)
Address Range (x16)
Block
Size
Block
Size
Block
Start
End
Start
End
255
128KB
1FE 0000h
1FF FFFFh
64KW
0FF 0000h
0FF FFFFh
⋮
127
⋮
⋮
⋮
⋮
⋮
0FE 0000h
0FF FFFFh
07F 0000h
07F FFFFh
⋮
⋮
⋮
⋮
63
⋮
07E 0000h
⋮
07F FFFFh
⋮
03F 0000h
⋮
03F FFFFh
⋮
0
000 0000h
001 FFFFh
000 0000h
000 FFFFh
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m29w_256mb.pdf - Rev. C 7/13 EN
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