Hi Tommy,

Just to let you know, I have just added some LEDs on PORT 0xA to your the JS simulator.

I saved the web page and can only get it to run in Chrome at the moment.

I then added a <textarea> and some <IMG> and code to emulate LEDS connected to port 0xa.

I could use the NAS-SYS3 command to set the LEDs. I also wrote a simpe BASIC program to turn them on and off.

A really good emulator is:http://www.donnelly-house.net/programming/cdp1802/simelf/ 
( click on a memory chip to open the GUI )

Many regards again,

regards,

Doug

Appendix: Added code


===========================
in nascom.js 

function writeport(port, value) {
    port &= 255;

...
    if (port == 1) {
        console.log("serial out " + value);
    }
/* doug rice */
    if (port == 10) {
      if (document.getElementById("io"))
        document.getElementById("io").value = "port 10:"+value;
    

      if (document.getElementById("led1")){
        var x=document.getElementById("led1")
        if ( ( value & 1 )==0){         
            x.setAttribute("src", "grey.png");
        } else {
            x.setAttribute("src", "red.png");
        }
      }

      if (document.getElementById("led2")){
        var x=document.getElementById("led2")
        if ( ( value & 2 )==0){         
            x.setAttribute("src", "grey.png");
        } else {
            x.setAttribute("src", "red.png");
        }
      }
      if (document.getElementById("led3")){
        var x=document.getElementById("led3")
        if ( ( value & 4 )==0){         
            x.setAttribute("src", "grey.png");
        } else {
            x.setAttribute("src", "red.png");
        }
      }

      if (document.getElementById("led4")){
        var x=document.getElementById("led4")
        if ( ( value & 8 )==0){         
            x.setAttribute("src", "grey.png");
        } else {
            x.setAttribute("src", "red.png");
        }
      }

    }


/*end - doug rice */


============================

In /jsnascom.html I added

    <a href="http://www.nascomhomepage.com/asm/Nap.txt">Nap</a><BR>
    <textarea id="io">
hello
    </textarea><BR>
    PORT 0xA:
    <img id="led4" src=red.png>
    <img id="led3" src=red.png>
    <img id="led2" src=red.png>
    <img id="led1" src=red.png>
 
<script>
    if (document.getElementById("io"))
        document.getElementById("io").value = "io-found";
/*
    if (document.getElementById("led2")){
        var x=document.getElementById("led2")
            x.setAttribute("src", "grey.png");
    }
*/

</script>