hi,

If you notice the control lines(WR and RD included)in most cases (from microprocessors, microcontrollers to the IBM parallel port) are all active low. Also, lines which expect a strobe input are all active low (like interrupt pins, STR, OE etc).

this is because it is critical that the control lines are not affected by noise. in some cases, it may be ok to have error in the data lines but its NEVER ok to have an error in the control lines.

kodi