http://pdf1.alldatasheet.com/datasheet-pdf/view/47662/WINBOND/W29C020/datasheet.pdf И далее про запись.

The read operation of the W29C020 is controlled by CE and OE, both of which have to be low for
the host to obtain data from the outputs. CE is used for device selection. When CE is high, the chip
is de-selected and only standby power will be consumed.
OE is the output control and is used to gate
data from the output pins. The data bus is in high impedance state when either CE or OE is high.
Refer to the read cycle timing waveforms for further details.