diff --git a/cm_pcf8574_driver.c b/cm_pcf8574_driver.c
index 6fef72a..f65305c 100644
--- a/cm_pcf8574_driver.c
+++ b/cm_pcf8574_driver.c
@@ -5,8 +5,21 @@
  *      Author: Chris
  */
 #include "cm_pcf8574_driver.h"
+#include <stddef.h>
 
-int cm_pcf8574_RegTransEvt(cm_pcf8574_t inst, void i2c_inst, setGet_I2C_Event_fpt i2c_transfer_evt){
+#define NUM_OF_RETRYS 3
+
+static int checkInst(cm_pcf8574_t *inst){
+
+	if(inst->i2c_transfer_evt == NULL)return CM_PCF8574_NOK;
+	if(inst->i2c_inst == NULL)return CM_PCF8574_NOK;
+
+	return CM_PCF8574_OK;
+
+
+}
+
+int cm_pcf8574_RegTransEvt(cm_pcf8574_t *inst, void *i2c_inst, setGet_I2C_Event_fpt i2c_transfer_evt){
 
 	if(inst == NULL) return CM_PCF8574_NOK;
 
@@ -19,3 +32,47 @@ int cm_pcf8574_RegTransEvt(cm_pcf8574_t inst, void i2c_inst, setGet_I2C_Event_fp
 
 
 }
+
+
+/*// No need to do this.. because I2C driver does this for us..
+int cm_pcf8574_IsDeviceActive(cm_pcf8574_t *inst){
+
+	if(checkInst(inst)) return CM_PCF8574_NOK;
+
+	uint8_t tx_buf[1] = {0};
+	uint8_t ret = 0;
+
+	for(uint8_t retry_ctr = 0; retry_ctr < NUM_OF_RETRYS; retry_ctr++){
+
+		ret = inst->i2c_transfer_evt(inst->i2c_inst, (uint8_t*)&tx_buf, 2, CM_PCF8574_I2C_GET);
+
+		if(ret == 0)return 0;
+
+	}
+
+	return ret;
+}*/
+int cm_pcf8574_SetPort(cm_pcf8574_t *inst, uint8_t port_val){
+
+	if(checkInst(inst)) return CM_PCF8574_NOK;
+
+	//inst->Port_1 = (cm_io_port_t)port_val;
+
+	return inst->i2c_transfer_evt(inst->i2c_inst, (uint8_t*)&port_val, sizeof(inst->Port_1), CM_PCF8574_I2C_SET);
+
+
+
+
+
+return 0;
+}
+
+// ret = inst->i2c_transfer_evt(inst->i2c_transfer_inst, (uint8_t*)&tx_buf, 2, LTR390_I2C_SET);
+int cm_pcf8574_Init(cm_pcf8574_t *inst){
+
+	if(checkInst(inst)) return CM_PCF8574_NOK;
+
+	//return cm_pcf8574_IsDeviceActive(inst);
+
+	return 0;
+}
diff --git a/cm_pcf8574_driver.h b/cm_pcf8574_driver.h
index 161e015..e43ba93 100644
--- a/cm_pcf8574_driver.h
+++ b/cm_pcf8574_driver.h
@@ -8,11 +8,19 @@
 #ifndef PCF8574_IO_EXPANDER_CM_PCF8574_DRIVER_H_
 #define PCF8574_IO_EXPANDER_CM_PCF8574_DRIVER_H_
 
+#include "stdint.h"
+
 enum{
 	CM_PCF8574_OK = 0,
 	CM_PCF8574_NOK
 };
 
+enum{
+	CM_PCF8574_I2C_GET = 0,
+	CM_PCF8574_I2C_SET = 1,
+
+};
+
 typedef int (*setGet_I2C_Event_fpt)(void *inst, uint8_t *data, uint32_t len, uint8_t set_get);
 
 
@@ -38,7 +46,8 @@ typedef struct{
 
 }cm_pcf8574_t;
 
-int cm_pcf8574_RegTransEvt(cm_pcf8574_t inst, void i2c_inst, setGet_I2C_Event_fpt i2c_transfer_evt);
-int cm_pcf8574_init(cm_pcf8574_t *inst);
+int cm_pcf8574_SetPort(cm_pcf8574_t *inst, uint8_t port_val);
+int cm_pcf8574_RegTransEvt(cm_pcf8574_t *inst, void *i2c_inst, setGet_I2C_Event_fpt i2c_transfer_evt);
+int cm_pcf8574_Init(cm_pcf8574_t *inst);
 
 #endif /* PCF8574_IO_EXPANDER_CM_PCF8574_DRIVER_H_ */