# SRAM HM6264 chip write cycle while output enabled (OE low fixed)

During SRAM write cycle, usually the !OE is disabled, while !WE and !CS are enabled. But for HM6264 SRAM chip (http://esd.cs.ucr.edu/webres/hm6264b.pdf), it allows the !OE to be enabled during write cycle.

it seems it either causes BUS contention or writes its own data? (i.e., write what it reads from itself).

Any thoughts?

• I thought, and I stress thought, that 6264 internally gates off the bus drivers while /WE is enabled, regardless of /OE. But I'm not dead certain. – TonyM May 16 '17 at 17:03

$WE/$ turns off the output drivers during the write cycle so no it does not write it's own data.
HOWEVER, when driving the chip in this mode, you need to drop $WE/$ before you apply the write data to the data pins. Data should not be driven onto the bus from the writer till after $T_{whz}$ later. Further, when $WE/$ is brought high you must remove your driving data before $T_{oz}$ time expires but not before $T_{DH}$ expires.
Unless there is a pressing reason not to use $OE/$ I strongly suggest you use it.