CAT28F512T-90T View Datasheet(PDF) - Catalyst Semiconductor => Onsemi

Part Name

Description

Manufacturer

CAT28F512T-90T

512K-Bit CMOS Flash Memory

Catalyst Semiconductor => Onsemi 

CAT28F512

READ OPERATIONS

Read Mode

A Read operation is performed with both CE and OE low

and with WE high. VPP can be either high or low,

however, if VPP is high, the Set READ command has to

be sent before reading data (see Write Operations). The

data retrieved from the I/O pins reflects the contents of

the memory location corresponding to the state of the 16

address pins. The respective timing waveforms for the

read operation are shown in Figure 3. Refer to the AC

Read characteristics for specific timing parameters.

Signature Mode

The signature mode allows the user to identify the IC

manufacturer and the type of device while the device

resides in the target system. This mode can be activated

in either of two ways; through the conventional method

of applying a high voltage (12V) to address pin A9 or by

sending an instruction to the command register (see

Write Operations).

The conventional mode is entered as a regular READ

mode by driving the CE and OE pins low (with WE high),

and applying the required high voltage on address pin A9

while all other address lines are held at VIL.

A Read cycle from address 0000H retrieves the binary

code for the IC manufacturer on outputs I/O0 to I/O7:

CATALYST Code = 00110001 (31H)

A Read cycle from address 0001H retrieves the binary

code for the device on outputs I/O0 to I/O7.

28F512 Code = 1011 1000 (B8H)

Standby Mode

With CE at a logic-high level, the CAT28F512 is placed

in a standby mode where most of the device circuitry is

disabled, thereby substantially reducing power con-

sumption. The outputs are placed in a high-impedance

state.

Figure 3. A.C. Timing for Read Operation

POWER UP

STANDBY

DEVICE AND

ADDRESS SELECTION

OUPUTS

ENABLED

DATA VALID STANDBY POWER DOWN

ADDRESSES

CE (E)

OE (G)

WE (W)

DATA (I/O)

HIGH-Z

ADDRESS STABLE

tAVAV (tRC)

tEHQZ (tDF)

tWHGL

tGLQV (tOE)

tGLQX (tOLZ)

tELQX (tLZ)

tGHQZ (tDF)

tELQV (tCE)

tAXQX (tOH)

OUTPUT VALID

HIGH-Z

tAVQV (tACC)

Doc. No. 1084, Rev. H

8

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