8
MX29F004T/B
P/N:PM0554
REV. 1.9, OCT. 19, 2004
READ/RESET COMMAND
The read or reset operation is initiated by writing the read/
reset command sequence into the command register.
Microprocessor read cycles retrieve array data. The de-
vice remains enabled for reads until the command regis-
ter contents are altered.
If program-fail or erase-fail happen, the write of F0H will
reset the device to abort the operation. A valid com-
mand must then be written to place the device in the
desired state.
SILICON-ID-READ COMMAND
Flash memories are intended for use in applications where
the local CPU alters memory contents. As such, manu-
facturer and device codes must be accessible while the
device resides in the target system. PROM program-
mers typically access signature codes by raising A9 to
a high voltage. However, multiplexing high voltage onto
address lines is not generally desired system design prac-
tice.
The MX29F004T/B contains a Silicon-ID-Read operation
to supplement traditional PROM programming method-
ology. The operation is initiated by writing the read sili-
con ID command sequence into the command register.
Following the command write, a read cycle with
A1=VIL,A0=VIL retrieves the manufacturer code of C2H.
A read cycle with A1=VIL, A0=VIH returns the device
code of 45H/46H for MX29F004T/B.
SET-UP AUTOMATIC CHIP/SECTOR ERASE
Chip erase is a six-bus cycle operation. There are two
"unlock" write cycles. These are followed by writing the
"set-up" command 80H. Two more "unlock" write cy-
cles are then followed by the chip erase command 10H.
The Automatic Chip Erase does not require the device
to be entirely pre-programmed prior to executing the Au-
tomatic Chip Erase. Upon executing the Automatic Chip
Erase, the device will automatically program and verify
the entire memory for an all-zero data pattern. When the
device is automatically verified to contain an all-zero
pattern, a self-timed chip erase and verify begin. The
erase and verify operations are completed when the data
on Q7 is "1" at which time the device returns to the
Read mode. The system is not required to provide any
control or timing during these operations.
When using the Automatic Chip Erase algorithm, note
that the erase automatically terminates when adequate
erase margin has been achieved for the memory array
(no erase verification command is required).
If the Erase operation was unsuccessful, the data on
Q5 is "1" (see Table 4), indicating the erase operation
exceed internal timing limit.
The automatic erase begins on the rising edge of the
last WE or CE, whichever happens first pulse in the
command sequence and terminates when the data on
Q7 is "1" and the data on Q6 stops toggling for two con-
secutive read cycles, at which time the device returns
to the Read mode.
Pins
Manufacture code
Device code for MX29F004T VIH
Device code for MX29F004B VIH
Chip Protection Verification
A0
VIL
A1
VIL
VIL
VIL
VIH
VIH
Q7
1
0
0
0
0
Q6
1
1
1
0
0
Q5
0
0
0
0
0
Q4
0
0
0
0
0
Q3
0
0
0
0
0
Q2
0
1
1
0
0
Q1
1
0
1
0
0
Q0
0
1
0
1
0
Code (Hex)
C2H
45H
46H
01H(Protected)
00H(Unprotected)
X
X
TABLE 3. EXPANDED SILICON ID CODE