diff --git a/bootloader/sansa_as3525.c b/bootloader/sansa_as3525.c
index 48f21bc..f010cf7 100644
--- a/bootloader/sansa_as3525.c
+++ b/bootloader/sansa_as3525.c
@@ -48,6 +48,8 @@ void main(void)
     system_init();
     kernel_init();
 
+    enable_irq();
+
 #ifdef SANSA_C200V2
     /* stop here */
     while(1);
@@ -58,6 +60,10 @@ void main(void)
     _backlight_on();
 
     button_init_device();
+#ifdef SANSA_CLIP
+  /* Clip button matrix has 3 rows, and the driver reads 1 row per tick */
+    sleep(3);
+#endif
     int btn = button_read_device();
 
 #if !defined(SANSA_FUZE) && !defined(SANSA_CLIP)
@@ -79,8 +85,6 @@ void main(void)
         verbose = true;
     }
 
-    enable_irq();
-
     ret = storage_init();
     if(ret < 0)
         error(EATA,ret);
diff --git a/firmware/target/arm/as3525/sansa-clip/button-clip.c b/firmware/target/arm/as3525/sansa-clip/button-clip.c
index 2d2a3a6..6c252c4 100644
--- a/firmware/target/arm/as3525/sansa-clip/button-clip.c
+++ b/firmware/target/arm/as3525/sansa-clip/button-clip.c
@@ -7,6 +7,7 @@
  *                     \/            \/     \/    \/            \/
  * $Id$
  *
+ * Copyright (C) 2009 Bertrik Sikken
  * Copyright (C) 2008 François Dinel
  * Copyright (C) 2008 Rafaël Carré
  *
@@ -21,75 +22,116 @@
  ****************************************************************************/
 #include "button-target.h"
 #include "as3525.h"
+#include "kernel.h"
 
-void button_init_device(void)
-{
-    GPIOA_DIR &= ~((1<<7) | (1<<3));
-    GPIOB_DIR &= ~((1<<2) | (1<<1) | (1<<0));
-    GPIOC_PIN(4) = 0x00;
-    GPIOC_PIN(5) = 0x00;
-    GPIOC_PIN(6) = 0x00;
-    GPIOC_DIR |= ((1<<6) | (1<<5) | (1<<4));
-}
+/*  The Sansa Clip uses a button matrix that is scanned by selecting one of
+    three rows and reading back the button states from the columns.
 
-int button_read_device(void)
+    In this driver, a kernel tick task is used to alternate between rows.
+    In one tick, column data from one row is read back and then the next row
+    is selected for the following tick. This mechanism ensures that there is
+    plenty time between selecting a row and reading the colums, avoiding the
+    need for explicit delays.
+*/
+
+static int buttons = 0;
+
+static void button_tick(void)
 {
-    int result = 0;
+    static int row = 0;
+    int temp;
 
-    if(button_hold())
-        return result;
+    if(button_hold()) {
+        buttons = 0;
+        return;
+    }
 
-    /* direct GPIO connections */
+    temp = buttons;
 
+    /* direct GPIO connections */
     if (GPIOA_PIN(7))
-        result |= BUTTON_POWER;
+        temp |= BUTTON_POWER;
+    else
+        temp &= ~BUTTON_POWER;
 
     /* This is a keypad using C4-C6 as columns and B0-B2 as rows */
-    GPIOC_PIN(4) = (1<<4);
-    asm volatile("nop\nnop\nnop\nnop\nnop\n"); /* small delay */
+    switch (row) {
+
+    case 0:
+        temp &= ~(BUTTON_VOL_UP | BUTTON_UP);
+
+        (void)GPIOB_PIN(0); /* C4B0 is unused */
 
-    (void)GPIOB_PIN(0); /* C4B0 is unused */
+        if (GPIOB_PIN(1))
+            temp |= BUTTON_VOL_UP;
 
-    if (GPIOB_PIN(1))
-        result |= BUTTON_VOL_UP;
+        if (GPIOB_PIN(2))
+            temp |= BUTTON_UP;
 
-    if (GPIOB_PIN(2))
-        result |= BUTTON_UP;
+        GPIOC_PIN(4) = 0;
+        GPIOC_PIN(5) = (1<<5);
+        row++;
+        break;
 
-    GPIOC_PIN(4) = 0x00;
+    case 1:
+        temp &= ~(BUTTON_LEFT | BUTTON_SELECT | BUTTON_RIGHT);
 
-    GPIOC_PIN(5) = (1<<5);
-    asm volatile("nop\nnop\nnop\nnop\nnop\n"); /* small delay */
+        if (GPIOB_PIN(0))
+            temp |= BUTTON_LEFT;
 
-    if (GPIOB_PIN(0))
-        result |= BUTTON_LEFT;
+        if (GPIOB_PIN(1))
+            temp |= BUTTON_SELECT;
 
-    if (GPIOB_PIN(1))
-        result |= BUTTON_SELECT;
+        if (GPIOB_PIN(2))
+            temp |= BUTTON_RIGHT;
 
-    if (GPIOB_PIN(2))
-        result |= BUTTON_RIGHT;
+        GPIOC_PIN(5) = 0;
+        GPIOC_PIN(6) = (1<<6);
+        row++;
+        break;
 
-    GPIOC_PIN(5) = 0x00;
+    case 2:
+        temp &= ~(BUTTON_DOWN | BUTTON_VOL_DOWN | BUTTON_HOME);
 
-    GPIOC_PIN(6) = (1<<6);
-    asm volatile("nop\nnop\nnop\nnop\nnop\n"); /* small delay */
+        if (GPIOB_PIN(0))
+            temp |= BUTTON_DOWN;
 
-    if (GPIOB_PIN(0))
-        result |= BUTTON_DOWN;
+        if (GPIOB_PIN(1))
+            temp |= BUTTON_VOL_DOWN;
 
-    if (GPIOB_PIN(1))
-        result |= BUTTON_VOL_DOWN;
+        if (GPIOB_PIN(2))
+            temp |= BUTTON_HOME;
 
-    if (GPIOB_PIN(2))
-        result |= BUTTON_HOME;
+        GPIOC_PIN(6) = 0;
+        GPIOC_PIN(4) = (1<<4);
 
-    GPIOC_PIN(6) = 0x00;
+    default:
+        row = 0;
+        break;
+    }
 
-    return result;
+    buttons = temp;
+}
+
+int button_read_device(void)
+{
+    return buttons;
 }
 
 bool button_hold(void)
 {
     return (GPIOA_PIN(3) != 0);
 }
+
+void button_init_device(void)
+{
+    GPIOA_DIR &= ~((1<<7) | (1<<3));
+    GPIOB_DIR &= ~((1<<2) | (1<<1) | (1<<0));
+    GPIOC_PIN(4) = 0;
+    GPIOC_PIN(5) = 0;
+    GPIOC_PIN(6) = 0;
+    GPIOC_DIR |= ((1<<6) | (1<<5) | (1<<4));
+
+    tick_add_task(button_tick);
+}
+