diff --git a/firmware/target/arm/as3525/clock-target.h b/firmware/target/arm/as3525/clock-target.h
index a227f464ff..21fd4c65d2 100644
--- a/firmware/target/arm/as3525/clock-target.h
+++ b/firmware/target/arm/as3525/clock-target.h
@@ -21,6 +21,9 @@
 #ifndef CLOCK_TARGET_H
 #define CLOCK_TARGET_H
 
+/* returns clock divider, given maximal target frequency and clock reference */
+#define CLK_DIV(ref, target) ((ref + target - 1) / target)
+
 /* PLL */
 
 #define AS3525_PLLA_FREQ        248000000
@@ -39,28 +42,26 @@
 
 /* peripherals */
 
-#define AS3525_PCLK_FREQ        65000000
+#define AS3525_PCLK_FREQ        62000000
+#if (CLK_DIV(AS3525_PLLA_FREQ, AS3525_PCLK_FREQ) - 1) >= (1<<4) /* 4 bits */
+#error PCLK frequency is too low : clock divider will not fit !
+#endif
 
-#define AS3525_IDE_FREQ         90000000
+#define AS3525_IDE_FREQ         66000000
+#if (CLK_DIV(AS3525_PLLA_FREQ, AS3525_IDE_FREQ) - 1) >= (1<<4) /* 4 bits */
+#error IDE frequency is too low : clock divider will not fit !
+#endif
+
+#define AS3525_I2C_FREQ         400000
+#if (CLK_DIV(AS3525_PLLA_FREQ, AS3525_I2C_FREQ)) >= (1<<16) /* 2*8 bits */
+#error I2C frequency is too low : clock divider will not fit !
+#endif
+
+#define AS3525_DBOP_FREQ        32000000
+#if (CLK_DIV(AS3525_PCLK_FREQ, AS3525_DBOP_FREQ) - 1) >= (1<<3) /* 3 bits */
+#error DBOP frequency is too low : clock divider will not fit !
+#endif
 
 #define AS3525_SD_IDENT_FREQ    400000      /* must be between 100 & 400 kHz */
 
-#define AS3525_I2C_FREQ         400000
-
-/* LCD controller : varies on the models */
-#if     defined(SANSA_CLIP)
-#define AS3525_DBOP_FREQ        6000000
-#elif   defined(SANSA_M200V4)
-#define AS3525_DBOP_FREQ        8000000
-#elif   defined(SANSA_FUZE)
-#define AS3525_DBOP_FREQ        8000000
-#elif   defined(SANSA_E200V2)
-#define AS3525_DBOP_FREQ        8000000
-#elif   defined(SANSA_C200V2)
-#define AS3525_DBOP_FREQ        8000000
-#endif
-
-/* macro for not giving a target clock > at the one provided */
-#define CLK_DIV(ref, target) ((ref + target - 1) / target)
-
 #endif /* CLOCK_TARGET_H */
diff --git a/firmware/target/arm/as3525/sansa-c200v2/lcd-c200v2.c b/firmware/target/arm/as3525/sansa-c200v2/lcd-c200v2.c
index 88adcd9d96..0ffe0bdc8d 100644
--- a/firmware/target/arm/as3525/sansa-c200v2/lcd-c200v2.c
+++ b/firmware/target/arm/as3525/sansa-c200v2/lcd-c200v2.c
@@ -98,7 +98,7 @@ static void lcd_delay(int x)
 /* DBOP initialisation, do what OF does */
 static void ams3525_dbop_init(void)
 {
-    CGU_DBOP = (1<<3) | CLK_DIV(AS3525_PCLK_FREQ, AS3525_DBOP_FREQ);
+    CGU_DBOP = (1<<3) | (CLK_DIV(AS3525_PCLK_FREQ, AS3525_DBOP_FREQ) - 1);
 
     DBOP_TIMPOL_01 = 0xe167e167;
     DBOP_TIMPOL_23 = 0xe167006e;
diff --git a/firmware/target/arm/as3525/sansa-clip/lcd-ssd1303.c b/firmware/target/arm/as3525/sansa-clip/lcd-ssd1303.c
index 4669abdf7d..a88e5faa0a 100644
--- a/firmware/target/arm/as3525/sansa-clip/lcd-ssd1303.c
+++ b/firmware/target/arm/as3525/sansa-clip/lcd-ssd1303.c
@@ -70,7 +70,7 @@
 /* DBOP initialisation, do what OF does */
 static void ams3525_dbop_init(void)
 {
-    CGU_DBOP |= (1<<3) | CLK_DIV(AS3525_PCLK_FREQ, AS3525_DBOP_FREQ);
+    CGU_DBOP |= (1<<3) | (CLK_DIV(AS3525_PCLK_FREQ, AS3525_DBOP_FREQ) - 1);
 
     GPIOB_AFSEL = 0x08; /* DBOP on pin 3 */
     GPIOC_AFSEL = 0x0f; /* DBOP on pins 3:0 */
diff --git a/firmware/target/arm/as3525/sansa-e200v2/lcd-e200v2.c b/firmware/target/arm/as3525/sansa-e200v2/lcd-e200v2.c
index ef21893494..9e23dac340 100644
--- a/firmware/target/arm/as3525/sansa-e200v2/lcd-e200v2.c
+++ b/firmware/target/arm/as3525/sansa-e200v2/lcd-e200v2.c
@@ -108,7 +108,7 @@ static void lcd_delay(int x)
 /* DBOP initialisation, do what OF does */
 static void ams3525_dbop_init(void)
 {
-    CGU_DBOP = (1<<3) | CLK_DIV(AS3525_PCLK_FREQ, AS3525_DBOP_FREQ);
+    CGU_DBOP = (1<<3) | (CLK_DIV(AS3525_PCLK_FREQ, AS3525_DBOP_FREQ) - 1);
 
     DBOP_TIMPOL_01 = 0xe167e167;
     DBOP_TIMPOL_23 = 0xe167006e;
diff --git a/firmware/target/arm/as3525/sansa-fuze/lcd-fuze.c b/firmware/target/arm/as3525/sansa-fuze/lcd-fuze.c
index 141b890861..f0c85f53b4 100644
--- a/firmware/target/arm/as3525/sansa-fuze/lcd-fuze.c
+++ b/firmware/target/arm/as3525/sansa-fuze/lcd-fuze.c
@@ -50,7 +50,7 @@ static bool lcd_busy = false;
 
 static void as3525_dbop_init(void)
 {
-    CGU_DBOP = (1<<3) | CLK_DIV(AS3525_PCLK_FREQ, AS3525_DBOP_FREQ);
+    CGU_DBOP = (1<<3) | (CLK_DIV(AS3525_PCLK_FREQ, AS3525_DBOP_FREQ) - 1);
 
     DBOP_TIMPOL_01 = 0xe167e167;
     DBOP_TIMPOL_23 = 0xe167006e;