M65KA128AL datasheet(15/53 Pages) STMICROELECTRONICS

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M65KA128AL

Commands

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Commands

There are 16 commands that control the memory. Refer to Table 3: Commands, in

conjunction with the text descriptions below and to Table 3: Commands.

4.1

Mode Register Set command

The Mode Register Set command is issued by applying VIL to E, RAS, CAS and W and by

setting BA1 to ‘0’, and BA0 to ‘0’.

The Mode Register Set command must be executed after the Power-Up sequence prior to

issuing a Bank (Row) Active command.

The execution of a Mode Register Set command will re-program the Mode Register,

modifying its contents.

4.2

Extended Mode Register Set command

The Extended Mode Register Set command is issued by applying VIL to E, RAS, CAS and

W, and then by setting BA1 to ‘1’, and BA0 to ‘0’.

The Extended Mode Register Set command must be executed after the Power-Up

sequence prior to issuing a Bank (Row) Active command.

The execution of an Extended Mode Register Set command will re-program the Extended

Mode Register, modifying its contents.

4.3

Bank (Row) Activate command

The Bank (Row) Active command is used to activate a row in a specific bank of the device.

This command is initiated by driving E and RAS Low, VIL, and driving CAS and W High, VIH,

at the positive edge of the clock signal, K. The value on BA1 and BA0 selects the bank, and

the value on A0-A11 selects the row. The selected row remains active for column access

until a Precharge command is issued to the bank containing the row.

A minimum time of tRCD is required after issuing the Bank (Row) Active command prior to

initiating Read and Write operations from and to the activated bank.

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