diff --git a/config.h b/config.h
index da1562a..db2621f 100644
--- a/config.h
+++ b/config.h
@@ -2,6 +2,13 @@
 #ifndef _CONFIG_H
 #define _CONFIG_H
 
+// What machine do you want to use the Tapuino with. Currently this is a build-time only option
+// The C64 and Vic 20 machines seem to be close enough that the C64 timing will work for the Vic 20
+// The C16 seems to be very much more particular, support for this machine is still in pre-alpha
+#define MACHINE_C64 1
+//#define MACHINE_VIC 1
+//#define MACHINE_C16 1
+
 // LCD Definitions
 // I2C config and expander data lines
 #define LCD_USE_1602_LCD_MODULE
diff --git a/memstrings.c b/memstrings.c
index 36071ab..f40897f 100644
--- a/memstrings.c
+++ b/memstrings.c
@@ -34,6 +34,7 @@ const char S_CHDIR_FAILED[] PROGMEM = "CHDIR fail!";
 const char S_READ_FAILED[] PROGMEM = "READ fail!";
 const char S_OPEN_FAILED[] PROGMEM = "OPEN fail!";
 const char S_INVALID_TAP[] PROGMEM = "Invalid TAP!";
+const char S_INVALID_SIZE[] PROGMEM = "Invalid size!";
 
 const char S_LOADING[] PROGMEM = "Loading:";
 const char S_OPERATION_COMPLETE[] PROGMEM = "Complete!";
diff --git a/memstrings.c-it b/memstrings.c-it
index 190b8dd..cf5f6c1 100644
--- a/memstrings.c-it
+++ b/memstrings.c-it
@@ -34,6 +34,7 @@ const char S_CHDIR_FAILED[] PROGMEM = "Errore CHDIR!";
 const char S_READ_FAILED[] PROGMEM = "READ fallito!";
 const char S_OPEN_FAILED[] PROGMEM = "OPEN fallito!";
 const char S_INVALID_TAP[] PROGMEM = "TAP Invalido!";
+const char S_INVALID_SIZE[] PROGMEM = "Formato non valido!";
 
 const char S_LOADING[] PROGMEM = "Loading:";
 const char S_OPERATION_COMPLETE[] PROGMEM = "Completato!";
diff --git a/memstrings.h b/memstrings.h
index 29289d5..389fb8a 100644
--- a/memstrings.h
+++ b/memstrings.h
@@ -37,6 +37,7 @@ extern const char S_CHDIR_FAILED[];
 extern const char S_READ_FAILED[];
 extern const char S_OPEN_FAILED[];
 extern const char S_INVALID_TAP[];
+extern const char S_INVALID_SIZE[];
 extern const char S_LOADING[];
 extern const char S_OPERATION_COMPLETE[];
 extern const char S_OPERATION_ABORTED[];
diff --git a/tapuino.c b/tapuino.c
index 82c3ace..7947e43 100644
--- a/tapuino.c
+++ b/tapuino.c
@@ -22,14 +22,29 @@
 #include "fileutils.h"
 #include "menu.h"
 
+// thanks stack overflow 
+#if defined(MACHINE_C64) + defined(MACHINE_VIC) + defined(MACHINE_C16) != 1
+  #error Define exactly one of MACHINE_C64, MACHINE_VIC, MACHINE_C16
+#endif
+
+#ifdef MACHINE_C64
+  #define NTSC_CYCLES_PER_SECOND 1022272 
+  #define PAL_CYCLES_PER_SECOND  985248
+#elif MACHINE_VIC
+  #define NTSC_CYCLES_PER_SECOND 1022727
+  #define PAL_CYCLES_PER_SECOND  1108404
+#elif MACHINE_C16
+  #define NTSC_CYCLES_PER_SECOND 894886
+  #define PAL_CYCLES_PER_SECOND  886724
+#else
+  #error Define exactly one of MACHINE_C64, MACHINE_VIC, MACHINE_C16
+#endif
 
 #ifdef USE_NTSC_TIMING
-  #define CYCLES_PER_SECOND 1022730
-  #define CYCLE_MULT_RAW    (1000000.0 / CYCLES_PER_SECOND)
+  #define CYCLE_MULT_RAW    (1000000.0 / NTSC_CYCLES_PER_SECOND)
   #define CYCLE_MULT_8      (CYCLE_MULT_RAW * 8)
 #else
-  #define CYCLES_PER_SECOND 985248
-  #define CYCLE_MULT_RAW    (1000000.0 / CYCLES_PER_SECOND)
+  #define CYCLE_MULT_RAW    (1000000.0 / PAL_CYCLES_PER_SECOND)
   #define CYCLE_MULT_8      (CYCLE_MULT_RAW * 8.0)
 #endif
 
@@ -203,9 +218,9 @@ ISR(TIMER1_COMPA_vect) {
           g_pulse_length_save |= ((unsigned long) g_fat_buffer[g_read_index++]) << 16;
           g_pulse_length_save *= CYCLE_MULT_RAW;
           g_tap_file_pos += 3;
-          // format 2 is half-wave and timer is running at 2Mhz so double
-          g_pulse_length_save <<= 1;
         }
+        // format 2 is half-wave and timer is running at 2Mhz so double
+        g_pulse_length_save <<= 1;
       }
       
       if (g_pulse_length > 0xFFFF) {        // check to see if its bigger than 16 bits
@@ -293,8 +308,9 @@ int verify_tap(FILINFO* pfile_info) {
 
   // check size first
   if (g_tap_info.length != (pfile_info->fsize - 20)) {
-    lcd_title_P(S_INVALID_TAP);
-    return 0;
+    lcd_title_P(S_INVALID_SIZE);
+    g_tap_info.length = pfile_info->fsize - 20;
+    lcd_busy_spinner();
   }
   
   uint32_t* tap_magic = (uint32_t*) g_fat_buffer;