HT27LC010

Rev. 1.30

5

December 8, 2003

Functional Description

Operation Mode

All the operation modes are shown in the table following.

Mode

CE

OE

PGM

A0

A1

A9

VPP

Output

Read

X (2)

X

X

X

Dout

Output Disable

XX

X

X

High Z

Standby (TTL)

XX

X

X

X

High Z

Standby (CMOS)

± 0.3V

XX

X

X

X

High Z

Program

XX

X

Program Verify

XX

X

Product Inhibit

XX

X

X

X

High Z

Manufacturer Code (3)

1C

Device Code (3)

01

Notes: (1)

(2)

Programming of the HT27LC010

When the HT27LC010 is delivered, the chip has all

1024K bits in the

²ONE², or HIGH state. ²ZEROs² are

loaded into the HT27LC010 through programming.

The programming mode is entered when 12.5

±0.2V is

plied with 8 bits in parallel to the data pins.

The programming flowchart in Figure 3 shows the fast

interactive programming algorithm. The interactive al-

gorithm reduces programming time by using 30

msto

105

ms programming pulses and giving each address

only as many pulses as is necessary in order to reliably

program the data. After each pulse is applied to a given

address, the data in that address is verified. If the data is

not verified, additional pulses are given until it is verified

or until the maximum number of pulses is reached while

sequencing through each address of the HT27LC010.

This process is repeated while sequencing through

each address of the HT27LC010. This part of the pro-

each EPROM bit is programmed to a sufficiently high

threshold voltage. This ensures that all bits have suffi-

cient margin. After the final address is completed, the

±0.3V to

verify the entire memory.

Program Inhibit Mode

Programming of multiple HT27LC010 in parallel with dif-

ferent data is also easily accomplished by using the Pro-

gram Inhibit Mode. Except for CE, all like inputs of the

parallel HT27LC010 may be common. A TTL low-level

program pulse applied to an HT27LC010 CE input with

Vpp=12.5

±0.2V, PGM LOW, and OE HIGH will program

that HT27LC010. A high-level CE input inhibits the

HT27LC010 from being programmed.

Program Verify Mode

Verification should be performed on the programmed

bits to determine whether they were correctly pro-

grammed. The verification should be performed with OE

voltage.

Auto Product Identification

The Auto Product Identification mode allows the reading

out of a binary code from an EPROM that will identify its

manufacturer and the type. This mode is intended for

programming to automatically match the device to be

programmed with its corresponding programming algo-

rithm. This mode is functional in the 25

°C±5°C ambient

temperature range that is required when programming

the HT27LC010.

To activate this mode, the programming equipment must

force 12.0

±0.5V on the address line A9 of the

HT27LC010. Two identifier bytes may then be se-

quenced from the device outputs by toggling address

tion mode.

these two identifier bytes are given in the Mode Select

Table. All identifiers for the manufacturer and device