Cmsis Usart Problem in using on LPC1788

Hi,

im new on using cmsis 

i have a self developed board based on lpc1788 and i using keil for programing and development

i wrote this program as simple example for usart in lpc1788

but in debug session it return the (  // USART is not configured (mode not selected) ))

#include <UART_LPC17xx.h>

void usart1init(void);

static ARM_USART_SignalEvent_t *Uhandler;


int main(void){

	usart1init();
	while(1);
}

void usart1init(void){
	ARM_DRIVER_USART MySerial = Driver_USART1;
	char sir[5] = "leg";


MySerial.Initialize(*Uhandler);
MySerial.PowerControl(ARM_POWER_FULL);
MySerial.Send(&sir[0],sizeof(sir));

}

can u guide me ? where am i wrong on this code