diff --git a/javatari.js b/javatari.js
index bd17384f..4326d966 160000
--- a/javatari.js
+++ b/javatari.js
@@ -1 +1 @@
-Subproject commit bd17384fd2c6b020497e5e6a625a1b8130e39ea1
+Subproject commit 4326d966e3adf16a8abe4a83f1c98359a825b5d9
diff --git a/src/audio.ts b/src/audio.ts
index f9d5ae19..86c6be20 100644
--- a/src/audio.ts
+++ b/src/audio.ts
@@ -472,3 +472,20 @@ export var SampleAudio = function(clockfreq) {
     }
   }
 }
+
+
+export class SampledAudio {
+  sa;
+  constructor(sampleRate : number) {
+    this.sa = new SampleAudio(sampleRate);
+  }
+  feedSample(value:number, count:number) {
+    this.sa.feedSample(value, count);
+  }
+  start() {
+    this.sa.start();
+  }
+  stop() {
+    this.sa.stop();
+  }
+}
diff --git a/src/baseplatform.ts b/src/baseplatform.ts
index d8026ead..950b4958 100644
--- a/src/baseplatform.ts
+++ b/src/baseplatform.ts
@@ -17,7 +17,7 @@ export interface OpcodeMetadata {
 export interface CpuState {
   PC:number;
   EPC?:number; // effective PC (for bankswitching)
-  T?:number;
+  T?:number; // TODO: remove in favor of 'stable'
   o?:number;/*opcode*/
   SP?:number
   /*
diff --git a/src/nemu/cpu/MOS6502.ts b/src/nemu/cpu/MOS6502.ts
index afad2c40..224ed83b 100644
--- a/src/nemu/cpu/MOS6502.ts
+++ b/src/nemu/cpu/MOS6502.ts
@@ -61,7 +61,7 @@ var _MOS6502 = function() {
     // Internal decoding registers
     var T : number = -1;
     var opcode : number = -1;
-    var instruction;
+    var instruction : (() => void)[];
     var data : number = 0;
     var AD : number = 0;
     var BA : number = 0;
@@ -90,6 +90,7 @@ var _MOS6502 = function() {
     const bC = 0;
 
     // Auxiliary variables
+    // TODO
     //noinspection JSUnusedGlobalSymbols
     this.debug = false;
     //noinspection JSUnusedGlobalSymbols
@@ -1888,6 +1889,12 @@ var _MOS6502 = function() {
     this.getSP = function() { return SP; }
     this.getPC = function() { return PC; }
     this.getT = function() { return T; }
+    
+    this.isPCStable = function() {
+      // TODO: gotta fix base class first
+      //return T < 0 || T == instruction.length-1;
+      return T == 0;
+    }
 };
 
 export interface MOS6502State {
@@ -1909,7 +1916,7 @@ export class MOS6502 implements CPU, ClockBased, SavesState<MOS6502State>, Inter
     this.cpu.connectBus(bus);
   }
   advanceClock() {
-    if (this.interruptType && this.cpu.getT() == 0) {
+    if (this.interruptType && this.isStable()) {
       switch (this.interruptType) {
         case MOS6502Interrupts.NMI: this.cpu.setNMI(); break;
         case MOS6502Interrupts.IRQ: this.cpu.setIRQ(); break;
@@ -1920,7 +1927,7 @@ export class MOS6502 implements CPU, ClockBased, SavesState<MOS6502State>, Inter
   advanceInsn() {
     do {
       this.advanceClock();
-    } while (this.cpu.getT() != 0);
+    } while (!this.isStable());
   }
   reset() {
     this.cpu.reset();
@@ -1944,6 +1951,9 @@ export class MOS6502 implements CPU, ClockBased, SavesState<MOS6502State>, Inter
     this.cpu.loadState(s);
     this.interruptType = s.it;
   }
+  isStable() : boolean {
+    return this.cpu.isPCStable();
+  }
   // TODO: metadata
   // TODO: disassembler
 }
diff --git a/src/nemu/machine/apple2.ts b/src/nemu/machine/apple2.ts
index 77de2227..efed5a0b 100644
--- a/src/nemu/machine/apple2.ts
+++ b/src/nemu/machine/apple2.ts
@@ -1,7 +1,7 @@
 "use strict";
 
 import { MOS6502, MOS6502State } from "../cpu/MOS6502";
-import { Bus, RasterFrameBased, SavesState, AcceptsROM, noise, Resettable } from "../nemu";
+import { Bus, RasterFrameBased, SavesState, AcceptsROM, noise, Resettable, SampledAudioSource, SampledAudioSink } from "../nemu";
 import { KeyFlags } from "../../emu"; // TODO
 import { lzgmini } from "../../util";
 
@@ -26,11 +26,13 @@ interface AppleIIState extends AppleIIStateBase {
   c : MOS6502State;
 }
 
-export class AppleII implements Bus, Resettable, RasterFrameBased, AcceptsROM, AppleIIStateBase, SavesState<AppleIIState> {
+export class AppleII implements Bus, Resettable, RasterFrameBased, SampledAudioSource, AcceptsROM,
+  AppleIIStateBase, SavesState<AppleIIState> {
 
   ram = new Uint8Array(0x13000); // 64K + 16K LC RAM - 4K hardware + 12K ROM
   rom : Uint8Array;
   cpu = new MOS6502();
+  audio : SampledAudioSink;
   pixels : Uint32Array;
   grdirty = new Array(0xc000 >> 7);
   grparams = {dirty:this.grdirty, grswitch:GR_TXMODE, mem:this.ram};
@@ -75,6 +77,7 @@ export class AppleII implements Bus, Resettable, RasterFrameBased, AcceptsROM, A
   loadState(s) {
     this.cpu.loadState(s.c);
     this.ram.set(s.ram);
+    // TODO
   }
   reset() {
     this.cpu.reset();
@@ -175,13 +178,22 @@ export class AppleII implements Bus, Resettable, RasterFrameBased, AcceptsROM, A
   getVideoParams() {
     return {width:280, height:192};
   }
+  getAudioParams() {
+    return {sampleRate:cpuFrequency, stereo:false};
+  }
   connectVideo(pixels:Uint32Array) {
     this.pixels = pixels;
     this.ap2disp = pixels && new Apple2Display(this.pixels, this.grparams);
   }
-  advanceFrame() : number {
-    for (var i=0; i<cpuCyclesPerFrame; i++) {
+  connectAudio(audio:SampledAudioSink) {
+    this.audio = audio;
+  }
+  advanceFrame(maxCycles, trap) : number {
+    maxCycles = Math.min(maxCycles, cpuCyclesPerFrame);
+    for (var i=0; i<maxCycles; i++) {
+      if (trap && this.cpu.isStable() && trap()) break;
       this.cpu.advanceClock();
+      this.audio.feedSample(this.soundstate, 1);
     }
     this.ap2disp && this.ap2disp.updateScreen();
     return i;
@@ -290,105 +302,6 @@ const GR_HIRES    = 8;
 type AppleGRParams = {dirty:boolean[], grswitch:number, mem:Uint8Array};
 
 /*
-const _Apple2Platform = function(mainElement) {
-  const cpuFrequency = 1023000;
-  const cpuCyclesPerLine = 65;
-
-  var cpu, ram, bus;
-  var video, ap2disp, audio, timer;
-  var grdirty = new Array(0xc000 >> 7);
-  var grswitch = GR_TXMODE;
-  var kbdlatch = 0;
-  var soundstate = 0;
-  var pgmbin;
-  // language card switches
-  var auxRAMselected = false;
-  var auxRAMbank = 1;
-  var writeinhibit = true;
-  // value to add when reading & writing each of these banks
-  // bank 1 is E000-FFFF, bank 2 is D000-DFFF
-  var bank2rdoffset=0, bank2wroffset=0;
-  var grparams : AppleGRParams;
-  var scanline : number;
-  
- class Apple2Platform extends Base6502Platform implements Platform {
-
-  getPresets() {
-    return APPLE2_PRESETS;
-  }
-  start() {
-      }
-    };
-    cpu.connectBus(bus);
-    // create video/audio
-    video = new RasterVideo(mainElement,280,192);
-    audio = new SampleAudio(cpuFrequency);
-    video.create();
-    video.setKeyboardEvents((key,code,flags) => {
-    });
-    var idata = video.getFrameData();
-    grparams = {dirty:grdirty, grswitch:grswitch, mem:ram.mem};
-    ap2disp = new Apple2Display(idata, grparams);
-    timer = new AnimationTimer(60, this.nextFrame.bind(this));
-  }
-  
-  advance(novideo : boolean) {
-    // 262.5 scanlines per frame
-    var clock = 0;
-    var debugCond = this.getDebugCallback();
-    for (var sl=0; sl<262; sl++) {
-      scanline = sl;
-      for (var i=0; i<cpuCyclesPerLine; i++) {
-        if (debugCond && debugCond()) {
-          debugCond = null;
-          sl = 999;
-          break;
-        }
-        clock++;
-        cpu.clockPulse();
-        audio.feedSample(soundstate, 1);
-      }
-    }
-    if (!novideo) {
-      grparams.dirty = grdirty;
-      grparams.grswitch = grswitch;
-      ap2disp.updateScreen();
-      video.updateFrame();
-    }
-  }
-  
-  getRasterScanline() : number {
-    return scanline;
-  }
-
-  loadROM(title, data) {
-    pgmbin = data;
-    this.reset();
-  }
-
-  isRunning() {
-    return timer.isRunning();
-  }
-  pause() {
-    timer.stop();
-    audio.stop();
-  }
-  resume() {
-    timer.start();
-    audio.start();
-  }
-  reset() {
-    cpu.reset();
-    // execute until $c600 boot
-    for (var i=0; i<2000000; i++) {
-      cpu.clockPulse();
-      if (this.getCPUState().PC == 0xc602) {
-        cpu.clockPulse();
-        cpu.clockPulse();
-        break;
-      }
-    }
-  }
   readAddress(addr : number) {
     return ((addr & 0xf000) != 0xc000) ? bus.read(addr) : null; // ignore I/O space
   }
@@ -426,10 +339,6 @@ const _Apple2Platform = function(mainElement) {
   getCPUState() {
     return this.fixPC(cpu.saveState());
   }
- }
-
-  return new Apple2Platform(); // return inner class from constructor
-};
 */
 
 var Apple2Display = function(pixels : Uint32Array, apple : AppleGRParams) {
diff --git a/src/nemu/nemu.ts b/src/nemu/nemu.ts
index e4a843e3..32f86fd9 100644
--- a/src/nemu/nemu.ts
+++ b/src/nemu/nemu.ts
@@ -18,16 +18,18 @@ export interface InstructionBased {
     advanceInsn() : number;
 }
 
+export type TrapCondition = () => boolean;
+
 export interface FrameBased {
-    advanceFrame() : number;
+    advanceFrame(maxClocks:number, trap:TrapCondition) : number;
 }
 
-export interface VideoFrameBased extends FrameBased {
+export interface VideoSource {
   getVideoParams() : VideoParams;
   connectVideo(pixels:Uint32Array) : void;
 }
 
-export interface RasterFrameBased extends VideoFrameBased {
+export interface RasterFrameBased extends FrameBased, VideoSource {
 }
 
 export interface VideoParams {
@@ -44,9 +46,14 @@ export interface SampledAudioParams {
     stereo : boolean;
 }
 
-export interface SampledAudio {
-    setAudioParams(params:SampledAudioParams) : void;
-    sendAudioFrame(samples:Uint16Array) : void;
+export interface SampledAudioSink {
+    feedSample(value:number, count:number) : void;
+    //sendAudioFrame(samples:Uint16Array) : void;
+}
+
+export interface SampledAudioSource {
+    getAudioParams() : SampledAudioParams;
+    connectAudio(audio : SampledAudioSink) : void;
 }
 
 export interface AcceptsROM {
@@ -94,7 +101,7 @@ export interface Hook<T> {
 
 export class BusHook implements Hook<Bus> {
   //target : Bus;
-  constructor(bus : Bus, profiler : ProfilerInterface) {
+  constructor(bus : Bus, profiler : LogBus) {
     //this.target = bus;
     var oldread = bus.read.bind(bus);
     var oldwrite = bus.write.bind(bus);
@@ -117,7 +124,7 @@ export class BusHook implements Hook<Bus> {
 
 export class CPUClockHook implements Hook<CPU&ClockBased> {
   //target : CPU&ClockBased;
-  constructor(cpu : CPU&ClockBased, profiler : ProfilerInterface) {
+  constructor(cpu : CPU&ClockBased, profiler : LogCPU) {
     //this.target = cpu;
     var oldclock = cpu.advanceClock.bind(cpu);
     cpu.advanceClock = () => {
@@ -133,7 +140,7 @@ export class CPUClockHook implements Hook<CPU&ClockBased> {
 
 export class CPUInsnHook implements Hook<CPU&InstructionBased> {
   //target : CPU&InstructionBased;
-  constructor(cpu : CPU&InstructionBased, profiler : ProfilerInterface) {
+  constructor(cpu : CPU&InstructionBased, profiler : LogCPU) {
     //this.target = cpu;
     var oldinsn = cpu.advanceInsn.bind(cpu);
     cpu.advanceInsn = () => {
@@ -149,13 +156,22 @@ export class CPUInsnHook implements Hook<CPU&InstructionBased> {
 
 /// PROFILER
 
-export interface ProfilerInterface {
+export interface LogCPU {
   logExecute(address:number);
+  logInterrupt(type:number);
+}
+
+export interface LogBus {
   logRead(address:number);
   logWrite(address:number);
+}
+
+export interface LogIO {
   logIORead(address:number);
   logIOWrite(address:number);
-  logInterrupt(type:number);
+}
+
+export interface LogAll extends LogCPU, LogBus, LogIO {
 }
 
 /// DEBUGGING
diff --git a/src/platform/apple2.ts b/src/platform/apple2.ts
index d75951dd..5847a28f 100644
--- a/src/platform/apple2.ts
+++ b/src/platform/apple2.ts
@@ -3,7 +3,7 @@
 import { Platform, Base6502Platform, BaseMAMEPlatform, getOpcodeMetadata_6502, getToolForFilename_6502 } from "../baseplatform";
 import { PLATFORMS, RAM, newAddressDecoder, padBytes, noise, setKeyboardFromMap, AnimationTimer, RasterVideo, Keys, KeyFlags, makeKeycodeMap, dumpRAM } from "../emu";
 import { hex, lzgmini } from "../util";
-import { SampleAudio } from "../audio";
+import { SampleAudio, SampledAudio } from "../audio";
 
 declare var jt; // 6502
 
@@ -1068,7 +1068,7 @@ class Apple2MAMEPlatform extends BaseMAMEPlatform implements Platform {
 ///
 
 // TODO: move to own place, debugging
-import { CPU, Bus, ClockBased, SavesState, Interruptable } from "../nemu/nemu";
+import { CPU, Bus, ClockBased, SavesState, Interruptable, CPUClockHook } from "../nemu/nemu";
 import { MOS6502 } from "../nemu/cpu/MOS6502";
 import { AppleII } from "../nemu/machine/apple2";
 
@@ -1078,6 +1078,7 @@ class NewApple2Platform extends Base6502Platform implements Platform {
   machine : AppleII;
   timer : AnimationTimer;
   video : RasterVideo;
+  audio : SampledAudio;
 
   constructor(mainElement : HTMLElement) {
     super();
@@ -1097,9 +1098,13 @@ class NewApple2Platform extends Base6502Platform implements Platform {
     this.timer = new AnimationTimer(60, this.nextFrame.bind(this));
     var vp = this.machine.getVideoParams();
     this.video = new RasterVideo(this.mainElement, vp.width, vp.height);
-    //this.audio = new SampleAudio(cpuFrequency);
     this.video.create();
+    this.video.setKeyboardEvents(this.machine.setInput.bind(this.machine));
     this.machine.connectVideo(this.video.getFrameData());
+    var ap = this.machine.getAudioParams();
+    this.audio = new SampledAudio(ap.sampleRate);
+    this.audio.start();
+    this.machine.connectAudio(this.audio);
   }
   reset() {
     this.machine.reset();
@@ -1109,7 +1114,7 @@ class NewApple2Platform extends Base6502Platform implements Platform {
     this.reset();
   }
   advance(novideo:boolean) {
-    this.machine.advanceFrame();
+    this.machine.advanceFrame(999999, this.getDebugCallback());
     if (!novideo) this.video.updateFrame();
   }
   isRunning() {
@@ -1117,9 +1122,24 @@ class NewApple2Platform extends Base6502Platform implements Platform {
   }
   resume() {
     this.timer.start();
+    this.audio.start();
   }
   pause() {
     this.timer.stop();
+    this.audio.stop();
+  }
+  // debugging
+  restartDebugging() {
+    super.restartDebugging();
+    // TODO
+    var clock = 0;
+    var cpuhook = new CPUClockHook(this.machine.cpu, {
+      logExecute: (a:number) => {
+        clock++;
+      },
+      logInterrupt: (a:number) => {
+      }
+    });
   }
 }
 
diff --git a/src/ui.ts b/src/ui.ts
index 8b6aac14..68ec9e7f 100644
--- a/src/ui.ts
+++ b/src/ui.ts
@@ -958,6 +958,7 @@ function measureBuildTime() {
     ga('send', 'timing', 'worker', 'build', (measureTimeBuild.getTime() - measureTimeLoad.getTime()));
     measureTimeLoad = null; // only measure once
   }
+  gaEvent('build', platform_id);
 }
 
 function setCompileOutput(data: WorkerResult) {