diff --git a/src/baseplatform.ts b/src/baseplatform.ts
new file mode 100644
index 00000000..4c275b4f
--- /dev/null
+++ b/src/baseplatform.ts
@@ -0,0 +1,48 @@
+
+export interface OpcodeMetadata {
+  minCycles: number;
+  // TODO
+}
+
+export interface Platform {
+  start() : void;
+  reset() : void;
+  isRunning() : boolean;
+  getToolForFilename(s:string) : string;
+  getDefaultExtension() : string;
+  getPresets() : Preset[];
+  pause() : void;
+  resume() : void;
+  loadROM(title:string, rom:Uint8Array);
+  
+  inspect?(ident:string) : void;
+  disassemble?(addr:number, readfn:(addr:number)=>number) : any; // TODO
+  readAddress?(addr:number) : number;
+  setFrameRate?(fps:number) : void;
+  getFrameRate?() : number;
+  cpuStateToLongString?(state) : string;
+  ramStateToLongString?(state) : string;
+  getRasterPosition() : {x:number, y:number};
+  setupDebug?(debugfn : (state)=>void) : void;
+  clearDebug?() : void;
+  step?() : void;
+  runToVsync?() : void;
+  runToPC?(pc:number) : void;
+  runUntilReturn?() : void;
+  stepBack?() : void;
+  //TODO runEval?(evalfn : (cpustate) => boolean) : void;
+  runEval?(evalfn : Function) : void;
+  
+  getOpcodeMetadata?(opcode:number, offset:number) : OpcodeMetadata; //TODO
+  saveState?() : any; // TODO
+  getDebugCallback?() : any; // TODO
+  getSP?() : number;
+}
+
+export interface Preset {
+  id : string;
+  name : string;
+  chapter? : number;
+  title? : string;
+}
+
diff --git a/src/project.ts b/src/project.ts
index 23f0e2ad..07d50f71 100644
--- a/src/project.ts
+++ b/src/project.ts
@@ -94,9 +94,9 @@ export class CodeProject {
   tools_preloaded = {};
   callbackBuildResult : BuildResultCallback;
   callbackBuildStatus : BuildStatusCallback;
-  worker: any;
+  worker : Worker;
   platform_id : string;
-  platform: any;
+  platform: any; // TODO: use type
   store: any;
   callbackGetRemote : GetRemoteCallback;
   mainPath: string;
diff --git a/src/ui.ts b/src/ui.ts
index fd9a418f..ed6f6226 100644
--- a/src/ui.ts
+++ b/src/ui.ts
@@ -6,6 +6,7 @@ import $ = require("jquery");
 import * as bootstrap from "bootstrap";
 import { SourceFile, CodeProject } from "./project";
 import { ProjectWindows } from "./windows";
+import { Platform, Preset } from "./baseplatform";
 import * as Views from "./views";
 
 // external libs (TODO)
@@ -18,43 +19,6 @@ declare var PLATFORMS;
 // make sure VCS doesn't start
 if (window['Javatari']) window['Javatari'].AUTO_START = false;
 
-interface Preset {
-  id : string;
-  name : string;
-  chapter? : number;
-  title? : string;
-}
-
-interface Platform {
-  start() : void;
-  reset() : void;
-  isRunning() : boolean;
-  getToolForFilename(s:string) : string;
-  getDefaultExtension() : string;
-  getPresets() : Preset[];
-  pause() : void;
-  resume() : void;
-  loadROM(title:string, rom:Uint8Array);
-  
-  inspect?(ident:string) : void;
-  disassemble?(addr:number, readfn:(addr:number)=>number) : any; // TODO
-  readAddress?(addr:number) : number;
-  setFrameRate?(fps:number) : void;
-  getFrameRate?() : number;
-  cpuStateToLongString?(state) : string;
-  ramStateToLongString?(state) : string;
-  getRasterPosition() : {x:number, y:number};
-  setupDebug?(debugfn : (state)=>void) : void;
-  clearDebug?() : void;
-  step?() : void;
-  runToVsync?() : void;
-  runToPC?(pc:number) : void;
-  runUntilReturn?() : void;
-  stepBack?() : void;
-  //TODO runEval?(evalfn : (cpustate) => boolean) : void;
-  runEval?(evalfn : Function) : void;
-}
-
 var PRESETS : Preset[];		// presets array
 var platform_id : string;	// platform ID string
 var platform : Platform;	// platform object
diff --git a/src/views.ts b/src/views.ts
index 81f1f352..55cbb737 100644
--- a/src/views.ts
+++ b/src/views.ts
@@ -2,6 +2,7 @@
 
 import $ = require("jquery");
 import { SourceFile, WorkerError, CodeProject } from "./project";
+import { Platform } from "./baseplatform";
 
 export interface ProjectView {
   createDiv(parent:HTMLElement, text:string) : HTMLElement;
@@ -18,7 +19,7 @@ export interface ProjectView {
 
 // TODO: move to different namespace
 declare var CodeMirror;
-declare var platform;
+declare var platform : Platform;
 declare var platform_id : string;
 declare var compparams;
 declare var addr2symbol : {[addr:number]:string};