AS29CF040-55CCIN datasheet(6/27 Pages) ALSC

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Requirements for Reading Array Data

To read array data from the outputs, the system must drive

the

CE and OE pins to VIL. CE is the power control and

selects the device.

OE is the output control and gates array

data to the output pins.

WE should remain at VIH all the time

during read operation. The internal state machine is set for

reading array data upon device power-up, or after a

hardware reset. This ensures that no spurious alteration of

the memory content occurs during the power transition. No

command is necessary in this mode to obtain array data.

Standard microprocessor read cycles that assert valid

addresses on the device address inputs produce valid data

on the device data outputs. The device remains enabled for

read access until the command register contents are altered.

See "Reading Array Data" for more information. Refer to the

AC Read Operations table for timing specifications and to the

Read Operations Timings diagram for the timing waveforms,

lCC1 in the DC Characteristics table represents the active

current specification for reading array data.

Writing Commands/Command Sequences

To write a command or command sequence (which includes

programming data to the device and erasing sectors of

memory), the system must drive

WE and CE to VIL, and

OE to VIH. An erase operation can erase one sector,

multiple sectors, or the entire device. The Sector Address

Tables indicate the address range that each sector occupies.

A "sector address" consists of the address inputs required to

uniquely select a sector. See the "Command Definitions"

section for details on erasing a sector or the entire chip, or

suspending/resuming the erase operation.

After the system writes the autoselect command sequence,

the device enters the autoselect mode. The system can then

read autoselect codes from the internal register (which is

separate from the memory array) on I/O7 - I/O0. Standard

read cycle timings apply in this mode. Refer to the

"Autoselect Mode" and "Autoselect Command Sequence"

sections for more information.

ICC2 in the Characteristics table represents the active current

specification for the write mode. The "AC Characteristics"

section contains timing specification tables and timing

diagrams for write operations.

Program and Erase Operation Status

During an erase or program operation, the system may

check the status of the operation by reading the status bits

on I/O7 - I/O0. Standard read cycle timings and ICC read

specifications apply. Refer to "Write Operation Status" for

more information, and to each AC Characteristics section for

timing diagrams.

Standby Mode

When the system is not reading or writing to the device, it

can place the device in the standby mode. In this mode,

current consumption is greatly reduced, and the outputs are

placed in the high impedance state, independent of the

input.

The device enters the CMOS standby mode when the

pin is held at VCC ± 0.5V. (Note that this is a more restricted

voltage range than VIH.) The device enters the TTL standby

mode when

CE is held at VIH. The device requires the

standard access time (tCE) before it is ready to read data.

If the device is deselected during erasure or programming,

the device draws active current until the operation is

completed.

ICC3 in the DC Characteristics tables represents the standby

current specification.

Output Disable Mode

When the

OE input is at VIH, output from the device is

disabled. The output pins are placed in the high impedance

state.

Table 2. Sector Addresses Table

Sector

A18

A17

A16

Address Range

SA0

00000h - 0FFFFh

SA1

10000h - 1FFFFh

SA2

20000h - 2FFFFh

SA3

30000h - 3FFFFh

SA4

40000h - 4FFFFh

SA5

50000h - 5FFFFh

SA6

60000h - 6FFFFh

SA7

70000h - 7FFFFh

Note: All sectors are 64 Kbytes in size.

AS29CF040-55CCIN

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Rev.1.0. July 2019

AS29CF040-55CCIN Datasheet(PDF) 6 Page - Alliance Semiconductor Corporation

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