AT49BV642D-70TU Atmel, AT49BV642D-70TU Datasheet - Page 4

• Manufacturer Part Number: AT49BV642D-70TU
• Description: IC FLASH 64MBIT 70NS 48TSOP
• Manufacturer: Atmel

Specifications of AT49BV642D-70TU

• Format - Memory: FLASH
• Memory Type: FLASH
• Memory Size: 64M (4M x 16)
• Speed: 70ns
• Interface: Parallel
• Voltage - Supply: 2.7 V ~ 3.6 V
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 48-TSOP
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

3.5
3.6
3.6.1
3.6.2
3.7
4
Word Programming
Sector Lockdown
Program/Erase Status
AT49BV642D(T)
Sector Lockdown Detection
Sector Lockdown Override
The device is programmed on a word-by-word basis. Programming is accomplished via the
internal device command register and is a four-bus cycle operation. The programming address
and data are latched in the fourth cycle. The device will automatically generate the required
internal programming pulses. Please note that a “0” cannot be programmed back to a “1”; only
erase operations can convert “0”s to “1”s.
Each sector has a programming lockdown feature. This feature prevents programming of data in
the designated sectors once the feature has been enabled. These sectors can contain secure
code that is used to bring up the system. Enabling the lockdown feature will allow the boot code
to stay in the device while data in the rest of the device is updated. This feature does not have to
be activated; any sector’s usage as a write-protected region is optional to the user.
At power-up or reset, all sectors are unlocked. To activate the lockdown for a specific sector, the
six-bus cycle Sector Lockdown command must be issued. Once a sector has been locked down,
the contents of the sector is read-only and cannot be erased or programmed.
A software method is available to determine if programming of a sector is locked down. When
the device is in the software product identification mode (see
Entry/Exit”
if programming the sector is locked down. If the data on I/O0 is low, the sector can be pro-
grammed; if the data on I/O0 is high, the program lockdown feature has been enabled and the
sector cannot be programmed. The software product identification exit code should be used to
return to standard operation.
The only way to unlock a sector that is locked down is through reset or power-up cycles. After
power-up or reset, the content of a sector that is locked down can be erased and reprogrammed.
The device provides several bits to determine the status of a program or erase operation: I/O2,
I/O3, I/O5, I/O6, and I/O7. All other status bits are don’t care. The
and the following four sections describe the function of these bits. To provide greater flexibility
for system designers, the AT49BV642D(T) contains a programmable configuration register. The
configuration register allows the user to specify the status bit operation. The configuration regis-
ter can be set to one of two different values, “00” or “01”. If the configuration register is set to
“00”, the part will automatically return to the read mode after a successful program or erase
operation. If the configuration register is set to a “01”, a Product ID Exit command must be given
after a successful program or erase operation before the part will return to the read mode. It is
important to note that whether the configuration register is set to a “00” or to a “01”, any unsuc-
cessful program or erase operation requires using the Product ID Exit command to return the
device to read mode. The default value (after power-up) for the configuration register is “00”.
Using the four-bus cycle set configuration register command as shown in the
tion Table” on page
to the reset pin will not alter the value of the configuration register. The value of the configuration
register will affect the operation of the I/O7 status bit as described below.
sections on
11, the value of the configuration register can be changed. Voltages applied
page
23), a read from address location 00002H within a sector will show
“Software Product Identification
“Status Bit Table” on page 10
“Command Defini-
3631A–FLASH–04/06