AT29C512-90JI Atmel, AT29C512-90JI Datasheet - Page 4

• Manufacturer Part Number: AT29C512-90JI
• Description: IC FLASH 512KBIT 90NS 32PLCC
• Manufacturer: Atmel

Specifications of AT29C512-90JI

• Format - Memory: FLASH
• Memory Type: FLASH
• Memory Size: 512K (64K x 8)
• Speed: 90ns
• Interface: Parallel
• Voltage - Supply: 4.5 V ~ 5.5 V
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 32-PLCC
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Other names: AT29C51290JI

4.4
4.5
4.6
4
Software Data Protection
Hardware Data Protection
Product Identification
AT29C512
A software controlled data protection feature is available on the AT29C512. Once the software
protection is enabled a software algorithm must be issued to the device before a program may
be performed. The software protection feature may be enabled or disabled by the user; when
shipped from Atmel, the software data protection feature is disabled. To enable the software
data protection, a series of three program commands to specific addresses with specific data
must be performed. After the software data protection is enabled the same three program com-
mands must begin each program cycle in order for the programs to occur. All software program
commands must obey the sector program timing specifications. Once set, the software data pro-
tection feature remains active unless its disable command is issued. Power transitions will not
reset the software data protection feature; however, the software feature will guard against inad-
vertent program cycles during power transitions.
Once set, software data protection will remain active unless the disable command sequence is
issued.
After setting SDP, any attempt to write to the device without the 3-byte command sequence will
start the internal write timers. No data will be written to the device; however, for the duration of
t
After the software data protection’s 3-byte command code is given, a byte load is performed by
applying a low pulse on the WE or CE input with CE or WE low (respectively) and OE high. The
address is latched on the falling edge of CE or WE, whichever occurs last. The data is latched by
the first rising edge of CE or WE. The 128 bytes of data must be loaded into each sector by the
same procedure as outlined in the program section under device operation.
Hardware features protect against inadvertent programs to the AT29C512 in the following ways:
(a) V
delay – once V
(typical) before programming; (c) Program inhibit – holding any one of OE low, CE high or WE
high inhibits program cycles; and (d) Noise filter – pulses of less than 15 ns (typical) on the WE
or CE inputs will not initiate a program cycle.
The product identification mode identifies the device and manufacturer as Atmel. It may be
accessed by hardware or software operation. The hardware operation mode can be used by an
external programmer to identify the correct programming algorithm for the Atmel product. In
addition, users may wish to use the software product identification mode to identify the part (i.e.,
using the device code), and have the system software use the appropriate sector size for pro-
gram operations. In this manner, the user can have a common board design for 256K to 4-
megabit densities and, with each density’s sector size in a memory map, have the system soft-
ware apply the appropriate sector size.
For details, see Operating Modes (for hardware operation) or Software Product Identification.
The manufacturer and device code is the same for both modes.
WC
, a read operation will effectively be a polling operation.
CC
sense – if V
CC
has reached the V
CC
is below 3.8V (typical), the program function is inhibited; (b) V
CC
sense level, the device will automatically time out 5 ms
0456i–FLASH–9/08
CC
power on