AT52BR1672-85CI ATMEL [ATMEL Corporation], AT52BR1672-85CI Datasheet - Page 6
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AT52BR1672-85CI
Manufacturer Part Number
AT52BR1672-85CI
Description
16-megabit Flash and 2-megabit/ 4-megabit SRAM Stack Memory
Manufacturer
ATMEL [ATMEL Corporation]
Datasheet
1.AT52BR1672-85CI.pdf
(39 pages)
Device
Operation
6
AT52BR1672(T)/1674(T)
READ: The 16-megabit Flash is accessed like an EPROM. When CE and OE are low and WE
is high, the data stored at the memory location determined by the address pins are asserted
on the outputs. The outputs are put in the high-impedance state whenever CE or OE is high.
This dual-line control gives designers flexibility in preventing bus contention.
COMMAND SEQUENCES: When the device is first powered on it will be reset to the read or
standby mode, depending upon the state of the control line inputs. In order to perform other
device functions, a series of command sequences are entered into the device. The command
sequences are shown in the Command Definitions table (I/O8 - I/O15 are don’t care inputs for
the command codes). The command sequences are written 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. Standard microprocessor write timings are used. The address locations used in the
command sequences are not affected by entering the command sequences.
RESET: A RESET input pin is provided to ease some system applications. When RESET is at
a logic high level, the device is in its standard operating mode. A low level on the RESET input
halts the present device operation and puts the outputs of the device in a high-impedance
state. When a high level is reasserted on the RESET pin, the device returns to the read or
standby mode, depending upon the state of the control inputs.
ERASURE: Before a word can be reprogrammed, it must be erased. The erased state of
memory bits is a logical “1”. The entire device can be erased by using the Chip Erase com-
mand or individual sectors can be erased by using the Sector Erase command.
CHIP ERASE: The entire device can be erased at one time by using the six-byte chip erase
software code. After the chip erase has been initiated, the device will internally time the erase
operation so that no external clocks are required. The maximum time to erase the chip is t
If the sector lockdown has been enabled, the chip erase will not erase the data in the sector
that has been locked out; it will erase only the unprotected sectors. After the chip erase, the
device will return to the read or standby mode.
SECTOR ERASE: As an alternative to a full chip erase, the device is organized into 39 sec-
tors (SA0 - SA38) that can be individually erased. The Sector Erase command is a six-bus
cycle operation. The sector address is latched on the falling WE edge of the sixth cycle while
the 30H data input command is latched on the rising edge of WE. The sector erase starts after
the rising edge of WE of the sixth cycle. The erase operation is internally controlled; it will
automatically time to completion. The maximum time to erase a section is t
tor programming lockdown feature is not enabled, the sector will erase (from the same Sector
Erase command). An attempt to erase a sector that has been protected will result in the oper-
ation terminating in 2 µs.
WORD PROGRAMMING: Once a memory block is erased, it is programmed (to a logical “0”)
on a word-by-word basis. Programming is accomplished via the internal device command reg-
ister and is a four-bus cycle operation. The device will automatically generate the required
internal program pulses.
Any commands written to the chip during the embedded programming cycle will be ignored. If
a hardware reset happens during programming, the data at the location being programmed
will be corrupted. Please note that a data “0” cannot be programmed back to a “1”; only erase
operations can convert “0”s to “1”s. Programming is completed after the specified t
time. The Data Polling feature or the Toggle Bit feature may be used to indicate the end of a
program cycle.
VPP PIN: The circuitry of the 16-megabit Flash is designed so that the device can be pro-
grammed or erased from the V
than or equal to the VCC pin, the device selects the V
CC
power supply or from the VPP input pin. When V
CC
supply for programming and erase
SEC
. When the sec-
2604B–STKD–09/02
PP
BP
is less
cycle
EC
.