diff --git a/src/emu.ts b/src/emu.ts
index 98a68525..32a58680 100644
--- a/src/emu.ts
+++ b/src/emu.ts
@@ -27,7 +27,7 @@ export function setNoiseSeed(x : number) {
   _random_state = x;
 }
 
-type KeyboardCallback = (which:number, charCode:number, flags:number) => void;
+type KeyboardCallback = (which:number, charCode:number, flags:KeyFlags) => void;
 
 function __createCanvas(mainElement:HTMLElement, width:number, height:number) : HTMLCanvasElement {
   var canvas = document.createElement('canvas');
@@ -39,15 +39,25 @@ function __createCanvas(mainElement:HTMLElement, width:number, height:number) :
   return canvas;
 }
 
+export enum KeyFlags {
+  KeyDown = 1,
+  Shift = 2,
+  Ctrl = 4,
+  Alt = 8,
+  Meta = 16,
+  KeyUp = 64,
+  KeyPress = 128,
+}
+
 function _setKeyboardEvents(canvas:HTMLElement, callback:KeyboardCallback) {
   canvas.onkeydown = function(e) {
-    callback(e.which, 0, 1|_metakeyflags(e));
+    callback(e.which, 0, KeyFlags.KeyDown|_metakeyflags(e));
   };
   canvas.onkeyup = function(e) {
-    callback(e.which, 0, 0|_metakeyflags(e));
+    callback(e.which, 0, KeyFlags.KeyUp|_metakeyflags(e));
   };
   canvas.onkeypress = function(e) {
-    callback(e.which, e.charCode, 1|_metakeyflags(e));
+    callback(e.which, e.charCode, KeyFlags.KeyPress|_metakeyflags(e));
   };
 };
 
@@ -396,7 +406,10 @@ export const Keys = {
 };
 
 function _metakeyflags(e) {
-  return (e.shiftKey?2:0) | (e.ctrlKey?4:0) | (e.altKey?8:0) | (e.metaKey?16:0);
+  return (e.shiftKey?KeyFlags.Shift:0) |
+        (e.ctrlKey?KeyFlags.Ctrl:0) | 
+        (e.altKey?KeyFlags.Alt:0) | 
+        (e.metaKey?KeyFlags.Meta:0);
 }
 
 export function setKeyboardFromMap(video, switches, map, func?) {
@@ -410,11 +423,11 @@ export function setKeyboardFromMap(video, switches, map, func?) {
       var mask = o.mask;
       if (mask < 0) { // negative mask == active low
         mask = -mask;
-        flags ^= 1;
+        flags ^= KeyFlags.KeyDown;
       }
-      if (flags & 1) {
+      if (flags & KeyFlags.KeyDown) {
         switches[o.index] |= mask;
-      } else {
+      } else if (flags & KeyFlags.KeyUp) {
         switches[o.index] &= ~mask;
       }
     }
diff --git a/src/platform/apple2.ts b/src/platform/apple2.ts
index 4ff1e599..9dd84fc4 100644
--- a/src/platform/apple2.ts
+++ b/src/platform/apple2.ts
@@ -1,7 +1,7 @@
 "use strict";
 
 import { Platform, Base6502Platform, BaseMAMEPlatform, getOpcodeMetadata_6502, getToolForFilename_6502 } from "../baseplatform";
-import { PLATFORMS, RAM, newAddressDecoder, padBytes, noise, setKeyboardFromMap, AnimationTimer, RasterVideo, Keys, makeKeycodeMap, dumpRAM } from "../emu";
+import { PLATFORMS, RAM, newAddressDecoder, padBytes, noise, setKeyboardFromMap, AnimationTimer, RasterVideo, Keys, KeyFlags, makeKeycodeMap, dumpRAM } from "../emu";
 import { hex, lzgmini } from "../util";
 import { SampleAudio } from "../audio";
 
@@ -164,27 +164,28 @@ const _Apple2Platform = function(mainElement) {
     audio = new SampleAudio(cpuFrequency);
     video.create();
     video.setKeyboardEvents((key,code,flags) => {
-      if (flags & 1) {
-        if (code) {
-          // convert to uppercase for Apple ][
-          if (code >= 0x61 && code <= 0x7a)
-             code -= 0x20; 
+      if (flags & KeyFlags.KeyPress) {
+        // convert to uppercase for Apple ][
+        if (code >= 0x61 && code <= 0x7a)
+           code -= 32; 
+        if (code >= 32) {
+          if (code >= 65 && code < 65+26) {
+            if (flags & KeyFlags.Ctrl)
+              code -= 64; // ctrl
+          }
           kbdlatch = (code | 0x80) & 0xff;
-        } else if (key) {
-          switch (key) {
-            case 16: return; // shift
-            case 17: return; // ctrl
-            case 18: return; // alt
-            case 37: key=8; break;	// left
-            case 39: key=21; break; // right
-            case 38: key=11; break; // up
-            case 40: key=10; break; // down
-          }
-          if (key >= 65 && key < 65+26) {
-            if (flags & 5) key -= 64; // ctrl
-          }
-          kbdlatch = (key | 0x80) & 0xff;
         }
+      } else if (flags & KeyFlags.KeyDown) {
+        code = 0;
+        switch (key) {
+          case 13: code=13; break; // return
+          case 37: code=8; break; // left
+          case 39: code=21; break; // right
+          case 38: code=11; break; // up
+          case 40: code=10; break; // down
+        }
+        if (code)
+          kbdlatch = (code | 0x80) & 0xff;
       }
     });
     var idata = video.getFrameData();