Hi,
I am trying understanding why on my development board CP-JR51AC2 V2, I can't find the ALE pin . I am trying to build the circuit attached. On Proteus it worked perfectly while on my breadboard I have noting. I figured that the inputs from P0.2 - P0.7 on the 74HC373 had no function at all in the simulation as without them every thing worked smoothly. Is this the same in reality, as in the schematic the same outputs of the other 6 flip flops are floating. thanks

 

I suggest reading the datasheet for your chip/board to find the ALE.

Possible datasheets; note, I am guessing it is the "T89C51AC2"; but Google can be wrong and since the board reference was not in English I could be wrong.
http://atmel.com/dyn/resources/prod_documents/doc4127.pdf
http://www.keil.com/dd/docs/datashts/atmel/t89c51ac2.pdf

Tim S.

 

Hi,
I figured that the inputs from P0.2 - P0.7 on the 74HC373 had no function at all in the simulation as without them every thing worked smoothly. Is this the same in reality, as in the schematic the same outputs of the other 6 flip flops are floating. thanks

In reality, letting inputs float can cause problems, I suggest connecting unused inputs to 74HC373 as high or low, not floating.

Tim S.