HY29F400 Просмотр технического описания (PDF) - Hynix Semiconductor

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HY29F400

4 Megabit (512Kx8/256Kx16) 5 Volt-only Flash Memory

Hynix Semiconductor 

HY29F400

Electronic ID Mode Operation

The Electronic ID mode provides manufacturer and

device identification and sector protection verifi-

cation through identifier codes output on DQ[7:0]

or DQ[15:0]. This mode is intended primarily for

programming equipment to automatically match

a device to be programmed with its correspond-

ing programming algorithm. The Electronic ID in-

formation can also be obtained by the host through

a command sequence, as described in the De-

vice Commands section.

Operation in the Electronic ID mode requires VID

on address pin A[9], with additional requirements

for obtaining specific data items as listed in Table

2:

n A read cycle at address 0xXXX00 retrieves the

manufacturer code (Hynix = 0xAD).

DEVICE COMMANDS

Device operations are initiated by writing desig-

nated address and data command sequences into

the device. A command sequence is composed

of one, two or three of the following sub-segments:

an unlock cycle, a command cycle and a data

cycle. Table 4 summarizes the composition of the

valid command sequences implemented in the

HY29F400, and these sequences are fully de-

scribed in Table 5 and in the sections that follow.

Writing incorrect address and data values or writ-

ing them in the improper sequence resets the

HY29F400 to the Read mode.

Read/Reset 1, 2 Commands

The HY29F400 automatically enters the Read

mode after device power-up, after the RESET#

input is asserted and upon the completion of cer-

tain commands. Read/Reset commands are not

required to retrieve data in these cases.

A Read/Reset command must be issued in order

to read array data in the following cases:

n If the device is in the Electronic ID mode, a

Read/Reset command must be written to re-

turn to the Read mode. If the device was in the

Erase Suspend mode when the device entered

the Electronic ID mode, writing the Read/Re-

set command returns the device to the Erase

Suspend mode.

n A read cycle at address 0xXXX01 returns the

device code:

- HY29F400T = 0x23 in Byte mode, 0x2223 in

Word mode.

- HY29F400B = 0xAB in Byte mode, 0x22AB

in Word mode.

n A read cycle containing a sector address (Table

1) in A[17:12] and the address 0x02 in A[7:0]

returns 0x01 if that sector is protected, or 0x00

if it is unprotected.

Table 4. Composition of Command Sequences

Command

Sequence

Number of Bus Cycles

Unlock Command Data

Read/Reset 1

0

1

Note 1

Read/Reset 2

2

1

Note 1

Byte Program

2

1

1

Chip Erase

4

1

1

Sector Erase

4

1

1 (Note 2)

Erase Suspend 0

1

0

Erase Resume

0

1

0

Electronic ID

2

1

Note 3

Notes:

1. Any number of Flash array read cycles are permitted.

2. Additional data cycles may follow. See text.

3. Any number of Electronic ID read cycles are permitted.

Note: When in the Electronic ID bus operation mode,

the device returns to the Read mode when VID is re-

moved from the A[9] pin. The Read/Reset command is

not required in this case.

n If DQ[5] (Exceeded Time Limit) goes High dur-

ing a program or erase operation, writing the

Read/Reset command returns the sectors to

the Read mode (or to the Erase Suspend mode

if the device was in Erase Suspend).

The Read/Reset command may also be used to

abort certain command sequences:

10

Rev. 5.2/May 01

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