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7

EN29F800

Rev. E, Issue Date: 2001/07/05

USER MODE DEFINITIONS

Word / Byte Configuration

The signal set on the BYTE# Pin controls whether the device data I/O pins DQ15-DQ0 operate in the

byte or word configuration. When the Byte# Pin is set at logic ‘1’, then the device is in word

configuration, DQ15-DQ0 are active and are controlled by CE# and OE#.

On the other hand, if the Byte# Pin is set at logic ‘0’, then the device is in byte configuration, and only

data I/O pins DQ0-DQ7 are active and controlled by CE# and OE#. The data I/O pins DQ8-DQ14

are tri-stated, and the DQ15 pin is used as an input for the LSB (A-1) address function.

Standby Mode

The EN29F800 has a CMOS-compatible standby mode, which reduces the current to

< 1µA (typical).

must also be at CMOS input levels. The device also has a TTL-compatible standby mode, which

Read Mode

The device is automatically set to reading array data after device power-up. No commands are required to

retrieve data. The device is also ready to read array data after completing an Embedded Program or

Embedded Erase algorithm.

After the device accepts an Erase Suspend command, the device enters the Erase Suspend mode. The

system can read array data using the standard read timings, except that if it reads at an address within

erase-suspended sectors, the device outputs status data. After completing a programming operation in

the Erase Suspend mode, the system may once again read array data with the same exception. See

“Erase Suspend/Erase Resume Commands” for more additional information.

The system

must issue the reset command to re-enable the device for reading array data if DQ5 goes

high, or while in the autoselect mode. See the “Reset Command” additional details.

Output Disable Mode

The output pins are placed in a high impedance state.

Auto Select Identification Mode

The autoselect mode provides manufacturer and device identification, and sector protection

verification, through identifier codes output on DQ15–DQ0. This mode is primarily intended for

programming equipment to automatically match a device to be programmed with its corresponding

programming algorithm. However, the autoselect codes can also be accessed in-system through the

command register.

address pin A9. Address pins A6, A1, and A0 must be as shown in Autoselect Codes (High Voltage

Method) table. In addition, when verifying sector protection, the sector address must appear on the

appropriate highest order address bits. Refer to the corresponding Sector Address Tables. The

Command Definitions table shows the remaining address bits that are don’t-care. When all

necessary bits have been set as required, the programming equipment may then read the

corresponding identifier code on DQ15–DQ0.