diff --git a/drivers/flash.c b/drivers/flash.c
index 3219253..3378d06 100644
--- a/drivers/flash.c
+++ b/drivers/flash.c
@@ -34,13 +34,15 @@ void flash_configure(enum FlashPreset preset)
 	//apply new configuration
 	switch (preset) {
 		case FLASH_PRESET_LOW_CLOCK_SPEED:
-			regs->ACR.HLFCYA = 0x1; //half cycle for power saving
+			reg_set(regs->ACR, FLASH_ACR_HLFCYA); //half cycle for power saving
 			break;
 		case FLASH_PRESET_MEDIUM_CLOCK_SPEED:
-			regs->ACR.LATENCY = 0x1;
+			reg_reset(regs->ACR, FLASH_ACR_LATENCY);
+			reg_write(regs->ACR, FLASH_ACR_LATENCY, 0x1);
 			break;
 		case FLASH_PRESET_HIGH_CLOCK_SPEED:
-			regs->ACR.LATENCY = 0x2;
+			reg_reset(regs->ACR, FLASH_ACR_LATENCY);
+			reg_write(regs->ACR, FLASH_ACR_LATENCY, 0x2);
 			break;
 		default:
 			break;
diff --git a/drivers/flash_regs.h b/drivers/flash_regs.h
index 26f4593..de1068a 100644
--- a/drivers/flash_regs.h
+++ b/drivers/flash_regs.h
@@ -11,6 +11,8 @@
 
 //--includes--------------------------------------------------------------------
 
+#include "reg.h"
+
 #include "stdint.h"
 
 
@@ -29,6 +31,12 @@ union FLASH_ACR {
 	uint32_t word;
 };
 
+#define FLASH_ACR_LATENCY	reg_def(0,  3)
+#define FLASH_ACR_HLFCYA	reg_def(3,  1)
+#define FLASH_ACR_PRFTBE	reg_def(4,  1)
+#define FLASH_ACR_PRFTBS	reg_def(5,  1)
+#define FLASH_ACR_reserved1 reg_def(6, 26)
+
 union FLASH_KEYR {
 	struct __attribute__((packed)) {
 		uint32_t reserved1; //TODO