Debugging with KEIL C51

A while ago I used an older version of the Keil simulator. It had a facility to perform a simulated action, then run the simulator for a given number of cycles, then perform another action. It sounds like what you want for your case.

Thad

Why don't you use KEIL software simulator which is built in IDE, and use Pheripheral PORT which you have keypad connected to and manualy give a pulse on port. And you can also use break points to avoid getting too many key press informations.

You seem to have missed out on the parts of the debug function syntax in Keil uVision that let a debug function wait for a specified amount of time, or until a given virtual register changes its state. Use those and you can generate both phases of your keypress in one call to a debug function, and thus in a single Toolbox button press.

I wrote a signal function to reset the PORT0 once that has been read . It is looks like signal void function() { while(1) { if(temp ==1) { exec("PORT0 = 0xFF") ; twatch(10) ; } } } Temp is set to 1 in 8051 code when a port has been read and readg is not 0xFF ie normal state where key is not pressed.

But some reason or other i am not getg desired response

thank you

As written, this will trigger *immediately* after your set temp=1, quite possibly before your code ever sees the port pins change.

Switch the order of the twatch() and the exec() and you should be in a better shape. I'm also quite sure it's not necessary to go through exec() to reset the port --- there's bound to be a VREG for that.

You may want to single-step through the code and watch the peripheral windows of the ports closely.