MBM29F040C datasheet(10/41 Pages) SPANSION

10 / 41 page

MBM29F040C-55/-70/-90

s FUNCTIONAL DESCRIPTION

Read Mode

The MBM29F040C has two control functions which must be satisfied in order to obtain data at the outputs. CE

is the power control and should be used for a device selection. OE is the output control and should be used to

gate data to the output pins if a device is selected.

Address access time (tACC) is equal to the delay from stable addresses to valid output data. The chip enable

access time (tCE) is the delay from stable addresses and stable CE to valid data at the output pins. The output

enable access time is the delay from the falling edge of OE to valid data at the output pins (assuming the

addresses have been stable for at least tACC-tOE time).

Standby Mode

The MBM29F040C has two standby modes, a CMOS standby mode (CE input held at VCC ±0.3 V.), when the

current consumed is less than 5 µA; and a TTL standby mode (CE is held at VIH) when the current required is

reduced to approximately 1 mA. During Embedded Algorithm operation, VCC Active current (ICC2) is required even

CE = VIH. The device can be read with standard access time (tCE) from either of these standby modes. In the

standby mode the outputs are in a high impedance state, independent of the OE input.

If the device is deselected during erasure or programming, the device will draw active current until the operation

is completed.

Output Disable

With the OE input at a logic high level (VIH), output from the device is disabled. This will cause the output pins

to be in a high impedance state.

Autoselect

The autoselect mode allows the reading out of a binary code from the device and will identify its manufacturer

and type. This mode is intended for use by programming equipment for the purpose of automatically matching

the device to be programmed with its corresponding programming algorithm. This mode is functional over the

entire temperature range of the device.

To activate this mode, the programming equipment must force VID (11.5 V to 12.5 V) on address pin A9. Two

identifier bytes may then be sequenced from the device outputs by toggling address A0 from VIL to VIH. All

addresses are DON’T CARES except A0, A1, and A6. (Recommend VIL for the other pins.)

The manufacturer and device codes may also be read via the command register, for instances when the

MBM29F040C is erased or programmed in a system without access to high voltage on the A9 pin. The command

sequence is illustrated in Table 5. (Refer to Autoselect Command section.)

Byte 0 (A0 = VIL) represents the manufacture’s code (Fujitsu = 04H) and byte 1 (A0 = VIH) represents the device

identifier code (MBM29F040C = A4H). These two bytes are given in the Table 3. All identifiers for manufactures

and device will exhibit odd parity with the MSB (DQ7) defined as the parity bit. In order to read the proper device

codes when executing the autoselect, A1 must be VIL. (See Table 3.)

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