diff --git a/Core/Inc/eeprom.h b/Core/Inc/eeprom.h
index 5f364c5..c4daf48 100644
--- a/Core/Inc/eeprom.h
+++ b/Core/Inc/eeprom.h
@@ -9,10 +9,10 @@
 
 //---------------------------------------------Datas registration--------------------------------------------
 
-#define EEPROM_VAR_ID	(0)		// 16b: Init ID: 0xCA1C
-#define EEPROM_VAR_CFG	(1)		// 16b: CFG + INT_CFG reg
-#define EEPROM_VAR_KBD	(2)		// 16b: DEB + FRQ regs
-#define EEPROM_VAR_BCKL	(3)		// 16b: LCD + KBD backlight step indice
+#define EEPROM_VAR_ID	(0)			// 16b: Init ID: 0xCA1C
+#define EEPROM_VAR_CFG	(1)			// 16b: CFG(15:8) + INT_CFG(7:0) reg
+#define EEPROM_VAR_KBD	(2)		// 32b: DEB(15:0) + 0x00 + FRQ(7:0) regs
+#define EEPROM_VAR_BCKL	(3)			// 16b: LCD(15:8) + KBD(7:0) backlight step indice
 
 //-------------------------------------------library configuration-------------------------------------------
 
diff --git a/Core/Inc/keyboard.h b/Core/Inc/keyboard.h
index 3b8db07..20567c8 100644
--- a/Core/Inc/keyboard.h
+++ b/Core/Inc/keyboard.h
@@ -83,6 +83,8 @@ void keyboard_set_key_callback(key_callback callback);
 void keyboard_set_lock_callback(lock_callback callback);
 uint8_t keyboard_get_capslock(void);
 uint8_t keyboard_get_numlock(void);
+uint16_t keyboard_get_hold_period(void);
+void keyboard_set_hold_period(uint16_t);
 void keyboard_process(void);
 
 
diff --git a/Core/Inc/regs.h b/Core/Inc/regs.h
index 07095f6..b400fd3 100644
--- a/Core/Inc/regs.h
+++ b/Core/Inc/regs.h
@@ -29,8 +29,8 @@ enum reg_id {
 	REG_ID_INT = 0x04,			//!< interrupt status
 	REG_ID_BKL = 0x05,			//!< backlight steps (0-9)
 	REG_ID_BK2 = 0x06,			//!< keyboard backlight (0-9)
-	REG_ID_DEB = 0x07,			//!< debounce cfg
-	REG_ID_FRQ = 0x08,			//!< poll freq cfg
+	REG_ID_DEB = 0x07,			//!< debounce cfg (time in ms)
+	REG_ID_FRQ = 0x08,			//!< poll freq cfg (time in ms)
 
 	REG_ID_KEY = 0x10,			//!< key status
 	REG_ID_FIF = 0x11,			//!< fifo
diff --git a/Core/Src/keyboard.c b/Core/Src/keyboard.c
index ab39b66..4cbcc3d 100644
--- a/Core/Src/keyboard.c
+++ b/Core/Src/keyboard.c
@@ -109,6 +109,7 @@ static uint8_t capslock_changed = 0;
 static uint8_t capslock = 0;
 static uint8_t numlock_changed = 0;
 static uint8_t numlock = 0;
+static uint16_t hold_period = KEY_HOLD_TIME;
 
 uint8_t io_matrix[9] = {0};		//for IO matrix,last byte is the restore key(c64 only)
 uint8_t js_bits = 0xFF;			// c64 joystick bits
@@ -130,6 +131,14 @@ inline uint8_t keyboard_get_numlock(void) {
 	return numlock & 0x1;
 }
 
+inline uint16_t keyboard_get_hold_period(void) {
+	return hold_period;
+}
+
+inline void keyboard_set_hold_period(uint16_t value) {
+	hold_period = value;
+}
+
 static void transition_to(struct list_item * const p_item, const enum key_state next_state) {
 	uint8_t output = 1;
 	const struct entry * const p_entry = p_item->p_entry;
@@ -272,7 +281,7 @@ static void next_item_state(struct list_item* const p_item, const uint8_t presse
 		break;
 
 	case KEY_STATE_PRESSED:
-		if (uptime_ms() > p_item->hold_start_time + KEY_HOLD_TIME) {
+		if (uptime_ms() > p_item->hold_start_time + hold_period) {
 			transition_to(p_item, KEY_STATE_HOLD);
 			p_item->last_repeat_time = uptime_ms();
 		} else if (!pressed)
@@ -283,7 +292,7 @@ static void next_item_state(struct list_item* const p_item, const uint8_t presse
 		if (!pressed)
 			transition_to(p_item, KEY_STATE_RELEASED);
 		else {
-			if (uptime_ms() > p_item->hold_start_time + KEY_HOLD_TIME) {
+			if (uptime_ms() > p_item->hold_start_time + hold_period) {
 				if(uptime_ms() > p_item->last_repeat_time + KEY_REPEAT_TIME) {
 					transition_to(p_item, KEY_STATE_HOLD);
 					p_item->last_repeat_time = uptime_ms();
@@ -305,7 +314,7 @@ static void next_item_state(struct list_item* const p_item, const uint8_t presse
 void keyboard_process(void) {
 	js_bits = 0xFF;
 
-	if (uptime_ms() <= (last_process_time + KEY_POLL_TIME))
+	if (uptime_ms() <= (last_process_time + reg_get_value(REG_ID_FRQ)))
 		return;
 
 	// Scan for columns
diff --git a/Core/Src/main.c b/Core/Src/main.c
index 0161951..42e69f6 100644
--- a/Core/Src/main.c
+++ b/Core/Src/main.c
@@ -26,8 +26,10 @@
 // Private define ------------------------------------------------------------
 //#define DEFAULT_LCD_BL	(205)	// ~40% PWM@7.81kHz (9 bits resolution)
 //#define DEFAULT_KBD_BL	(20)	// ~4% PWM@7.81kHz (9 bits resolution)
-#define DEFAULT_LCD_BL	(3)		//step-4 (~50%)
-#define DEFAULT_KBD_BL	(0)		//step-1 (0%)
+#define DEFAULT_LCD_BL		(3)		//step-4 (~50%)
+#define DEFAULT_KBD_BL		(0)		//step-1 (0%)
+#define DEFAULT_KBD_FREQ	(KEY_POLL_TIME)
+#define DEFAULT_KBD_DEB		(KEY_HOLD_TIME)
 
 #define I2CS_REARM_TIMEOUT	500
 #define I2CS_W_BUFF_LEN		31+1	// The last one must be only a 0 value, TODO: another cleaner way?
@@ -68,7 +70,7 @@ volatile uint32_t systicks_counter = 0;		// 1 MHz systick counter - TODO: implem
 volatile uint32_t pmu_check_counter = 0;
 volatile uint32_t i2cs_rearm_counter = 0;
 
-static uint8_t i2cs_r_buff[2];
+static uint8_t i2cs_r_buff[5];
 static volatile uint8_t i2cs_r_idx = 0;
 static uint8_t i2cs_w_buff[I2CS_W_BUFF_LEN];
 static volatile uint8_t i2cs_w_idx = 0;
@@ -129,6 +131,25 @@ extern void HAL_I2C_AddrCallback(I2C_HandleTypeDef *hi2c, uint8_t TransferDirect
 					if (is_write)
 						kbd_backlight_update(i2cs_r_buff[1]);
 					i2cs_w_buff[1] = reg_get_value(REG_ID_BK2);
+				} else if (reg == REG_ID_CFG) {
+					if (is_write)
+						reg_set_value(REG_ID_CFG, i2cs_r_buff[1]);
+					i2cs_w_buff[1] = reg_get_value(REG_ID_CFG);
+				} else if (reg == REG_ID_INT_CFG) {
+					if (is_write)
+						reg_set_value(REG_ID_INT_CFG, i2cs_r_buff[1]);
+					i2cs_w_buff[1] = reg_get_value(REG_ID_INT_CFG);
+				} else if (reg == REG_ID_DEB) {
+					if (is_write) {
+						keyboard_set_hold_period(*((uint16_t*)&i2cs_r_buff[1]));
+						reg_set_value(REG_ID_DEB, 0);	// Trig async flag for EEPROM saving
+					}
+					*((uint16_t*)&i2cs_w_buff[1]) = keyboard_get_hold_period();
+					i2cs_w_len = 3;
+				} else if (reg == REG_ID_FRQ) {
+					if (is_write)
+						reg_set_value(REG_ID_FRQ, i2cs_r_buff[1]);
+					i2cs_w_buff[1] = reg_get_value(REG_ID_FRQ);
 				} else if (reg == REG_ID_FIF) {
 					struct fifo_item item = {0};
 					fifo_dequeue(&item);
@@ -188,14 +209,24 @@ extern void HAL_I2C_SlaveRxCpltCallback(I2C_HandleTypeDef *hi2c) {
 		if (i2cs_state == I2CS_STATE_REG_REQUEST) {
 			const uint8_t is_write = (uint8_t)(i2cs_r_buff[0] & (1 << 7));
 			const uint8_t reg = (uint8_t)(i2cs_r_buff[0] & ~(1 << 7));
+			uint8_t bytes_needed = 0;
 
-			// We wait an another byte for these registers
+			// Check for another mandatories bytes depending on register requested
 			if (reg == REG_ID_BKL ||
-				reg == REG_ID_BK2) {
-				if (is_write) {
-					HAL_I2C_Slave_Sequential_Receive_IT(hi2c, i2cs_r_buff + i2cs_r_idx, 1, I2C_NEXT_FRAME);	// This write the second received byte to i2cs_r_buff[1]
-				}
+				reg == REG_ID_BK2 ||
+				reg == REG_ID_CFG ||
+				reg == REG_ID_INT_CFG ||
+				reg == REG_ID_FRQ) {
+				if (is_write)
+					bytes_needed = 1;
+
+			} else if (reg == REG_ID_DEB) {
+				if (is_write)
+					bytes_needed = 2;
 			}
+
+			if (bytes_needed > 0)
+				HAL_I2C_Slave_Sequential_Receive_IT(hi2c, i2cs_r_buff + i2cs_r_idx, bytes_needed, I2C_NEXT_FRAME);	// This write the second or more received byte to i2cs_r_buff[1]
 		}
 	}
 }
@@ -261,7 +292,7 @@ int main(void) {
 	EEPROM_ReadVariable(EEPROM_VAR_ID, (EEPROM_Value*)&result);
 	if ((uint16_t)result != 0xCA1C) {
 		EEPROM_WriteVariable(EEPROM_VAR_BCKL, (EEPROM_Value)(uint16_t)((DEFAULT_LCD_BL << 8) | DEFAULT_KBD_BL), EEPROM_SIZE16);
-		EEPROM_WriteVariable(EEPROM_VAR_KBD, (EEPROM_Value)(uint16_t)((10 << 8) | 5), EEPROM_SIZE16);
+		EEPROM_WriteVariable(EEPROM_VAR_KBD, (EEPROM_Value)(uint32_t)((DEFAULT_KBD_DEB << 16) | DEFAULT_KBD_FREQ), EEPROM_SIZE32);
 		EEPROM_WriteVariable(EEPROM_VAR_CFG, (EEPROM_Value)(uint16_t)(((CFG_USE_MODS | CFG_REPORT_MODS) << 8) | (INT_OVERFLOW | INT_KEY)), EEPROM_SIZE16);
 		EEPROM_WriteVariable(EEPROM_VAR_ID, (EEPROM_Value)(uint16_t)0xCA1C, EEPROM_SIZE16);
 #ifdef DEBUG
diff --git a/Core/Src/regs.c b/Core/Src/regs.c
index 4484906..4dacf6f 100644
--- a/Core/Src/regs.c
+++ b/Core/Src/regs.c
@@ -67,7 +67,7 @@ void reg_init(void) {
 	regs[REG_ID_INT_CFG] = (uint8_t)(buff & 0xFF);
 
 	EEPROM_ReadVariable(EEPROM_VAR_KBD, (EEPROM_Value*)&buff);
-	regs[REG_ID_DEB] = (uint8_t)((buff >> 8) & 0xFF);
+	//regs[REG_ID_DEB] = (uint8_t)((buff >> 8) & 0xFF);
 	regs[REG_ID_FRQ] = (uint8_t)(buff & 0xFF);
 
 	EEPROM_ReadVariable(EEPROM_VAR_BCKL, (EEPROM_Value*)&buff);
@@ -96,7 +96,7 @@ uint32_t reg_check_and_save_eeprom(void) {
 			result |= EEPROM_WriteVariable(EEPROM_VAR_CFG, (EEPROM_Value)(uint16_t)((regs[REG_ID_CFG] << 8) | regs[REG_ID_INT_CFG]), EEPROM_SIZE16);
 
 		if (regs_unsync[REG_ID_DEB] == 1 || regs_unsync[REG_ID_FRQ] == 1)
-			result |= EEPROM_WriteVariable(EEPROM_VAR_KBD, (EEPROM_Value)(uint16_t)((regs[REG_ID_DEB] << 8) | regs[REG_ID_FRQ]), EEPROM_SIZE16);
+			result |= EEPROM_WriteVariable(EEPROM_VAR_KBD, (EEPROM_Value)(uint32_t)((keyboard_get_hold_period() << 16) | regs[REG_ID_FRQ]), EEPROM_SIZE32);
 
 		if (regs_unsync[REG_ID_BKL] == 1 || regs_unsync[REG_ID_BK2] == 1)
 			result |= EEPROM_WriteVariable(EEPROM_VAR_BCKL, (EEPROM_Value)(uint16_t)((regs[REG_ID_BKL] << 8) | regs[REG_ID_BK2]), EEPROM_SIZE16);
diff --git a/Makefile b/Makefile
index 3fd66a9..3816b93 100644
--- a/Makefile
+++ b/Makefile
@@ -20,6 +20,8 @@ TARGET = picocalc_BIOS_jcs
 DEBUG = 0
 # optimization
 OPT = -O3
+# use old I2C registers structure
+I2C_REGS_COMPAT = 0
 
 
 #######################################
@@ -122,6 +124,10 @@ ifeq ($(DEBUG), 1)
 C_DEFS += -DDEBUG
 endif
 
+ifeq ($(I2C_REGS_COMPAT), 1)
+C_DEFS += -DI2C_REGS_COMPAT
+endif
+
 
 # AS includes
 AS_INCLUDES = 
diff --git a/README.md b/README.md
index 8df2724..8a744ec 100644
--- a/README.md
+++ b/README.md
@@ -7,15 +7,28 @@ PicoCalc STM32F103R8T6 firmware.
 The main differences with the original firmware are the followings:
 
 - drastic reduction in the STM32's electricity consumption when running (~3.5 mA),
-- clean up (in progress) to reduce binary size (~25 KB) and allow more features to be implemented,
-- removed stm32duino dependencies (use STM32HAL instead, maybe I'll switch to libopencm3 someday...),
+- clean up (by removing stm32duino dependencies, use STM32HAL instead, maybe I'll switch to libopencm3 someday...) to reduce binary size (~25 KB) and allow more features to be implemented,
 - added configuration saving solution (using internal flash, including backlight option),
+- new I2C registers and structure (keeping compatible access to REG_ID_TYP and REG_ID_VER registers to check how to handle comm from pico board side),
+- interrupt event output to pico board can be configured during runtime (for keyboard event or RTC alarm),
 - rewriten or added some debug UART interface message,
+- internal RTC access through dedicated I2C registers (WIP),
 - lighten AXP2101 PMIC driver.
 
 ## Compile
 This source code can be compiled using ARM gcc toolchain (using v13) in path and using make program.
 
+CAUTION: By default, I2C registers use a new, exploded structure that is more flexible! 
+But this makes them incompatible with official firmware. (More details to come about I2C registers structure in the wiki...)
+
+If you plan using pico official firmware (PicoMite, etc.), you should set I2C_REGS_COMPAT = 1 in the Makefile.
+
+## Important notes
+The current implementation of this firmware is subject to change until the v1 release.
+
+The permanent settings (EEPROM) save can be broken between 0.x version, it is recommanded to make a full flash erase before updating, as 
+EEPROM configuration survives update.
+
 ## Credits
 - STM32-HAL: [link](https://github.com/STMicroelectronics/stm32f1xx-hal-driver)
 - STM32-CMSIS: [link](https://github.com/STMicroelectronics/cmsis-device-f1)