AM29F040 データシートの表示（PDF） - Advanced Micro Devices
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AM29F040
Advanced Micro Devices
AM29F040 Datasheet PDF : 33 Pages
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Table 2. Am29F040 Autoselect Codes
Type
Code
A18 A17 A16 A6 A1 A0 (HEX) DQ7 DQ6 DQ5 DQ4 DQ3 DQ2 DQ1 DQ0
Manufacturer
ID
X
X
X
VIL VIL VIL 01H 0
0
0
0
0
0
0
1
Am29F040
Device ID
X
X
X
VIL VIL VIH A4H 1
0
1
0
0
1
0
0
Sector
Protection
Sector Addresses VIL VIH VIL 01H* 0
0
0
0
0
0
0
1
*Outputs 01H at protected sector addresses
Table 3. Sector Addresses
A18
A17
A16 Address Range
SA0
0
0
0 00000h–0FFFFh
SA1
0
0
1 10000h–1FFFFh
SA2
0
1
0 20000h–2FFFFh
SA3
0
1
1 30000h–3FFFFh
SA4
1
0
0 40000h–4FFFFh
SA5
1
0
1 50000h–5FFFFh
SA6
1
1
0 60000h–6FFFFh
SA7
1
1
1 70000h–7FFFFh
Write
Device erasure and programming are accomplished
via the command register. The contents of the register
serve as inputs to the internal state machine. The state
machine outputs dictate the function of the device.
The command register itself does not occupy any
addressable memory location. The register is a latch
used to store the commands, along with the address
and data information needed to execute the command.
The command register is written by bringing WE to VIL,
while CE is at VIL and OE is at VIH. Addresses are
latched on the falling edge of WE or CE, whichever
happens later; while data is latched on the rising edge
of WE or CE, whichever happens first. Standard
microprocessor write timings are used.
Refer to AC Write Characteristics and the Erase/
Programming Waveforms for specific timing parameters.
Sector Protection
The Am29F040 features hardware sector protection.
This feature will disable both program and erase
operations in any number of sectors (0 through 8). The
sector protect feature is enabled using programming
equipment at the user’s site. The device is shipped with
all sectors unprotected. Alternatively, AMD may pro-
gram and protect sectors in the factory prior to shipping
the device (AMD’s ExpressFlash™ Service).
It is also possible to determine if a sector is protected
in the system by writing an Autoselect command.
Performing a read operation at the address location
XX02H, where the higher order addresses (A16,
A17, and A18) are used to select the desired sector.
The device produces a logical “1” at DQ0 for a pro-
tected sector and a logical “0” for an unprotected
sector. See Table 2 for Autoselect codes.
Sector Unprotect
The Am29F040 also features a sector unprotect mode
so that a protected sector may be unprotected to
incorporate any changes in the code. The sector unpro-
tect is enabled using programming equipment at the
user’s site.
Command Definitions
Device operations are selected by writing specific ad-
dress and data sequences into the command register.
Writing incorrect address and data values or writing
them in the improper sequence will reset the device to
read mode. Table 4 defines the valid register command
sequences. Note that the Erase Suspend (B0) and
Erase Resume (30) commands are valid only while the
Sector Erase operation is in progress. Either of the two
reset commands will reset the device (when applicable).
8
Am29F040
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