STM8S105 2 channel ADC1 problem

[Knife]

Hi All

I want to read 2 channel ADC from ADC1 library. You can see my code below. I used scan mode and conversation mode single. I take 4 samples in interrupt and used average of them in my main code. My problem is sometimes ADC1_GetBufferValue(1) or ADC1_GetBufferValue(0) returns bigger than 1023. For example 20000, 40000 or something like that. Could you have any opinion for this issue ?

void ADC_Configuration(void)
{
	ADC1_DeInit();
	ADC1_Cmd(ENABLE);
	ADC1_Init(ADC1_CONVERSIONMODE_SINGLE, ADC1_CHANNEL_1, ADC1_PRESSEL_FCPU_D18, \
	ADC1_EXTTRIG_TIM, DISABLE, ADC1_ALIGN_RIGHT, ADC1_SCHMITTTRIG_ALL, DISABLE);
	ADC1_ScanModeCmd(ENABLE); 
	ADC1_ITConfig(ADC1_IT_EOCIE, ENABLE);
	ADC1_DataBufferCmd(ENABLE);
	ADC1_StartConversion();
}

INTERRUPT_HANDLER(ADC1_IRQHandler, 22)
 {

		ADC1_ClearITPendingBit(ADC1_IT_EOC);
		//ADC1_ClearFlag(ADC1_FLAG_EOC); 



		wBATTERY_VOLTAGE_SUM = wBATTERY_VOLTAGE_SUM + ADC1_GetBufferValue(1);
		byBATTERY_VOLTAGE_SAMPLE_COUNT++;

		if(byBATTERY_VOLTAGE_SAMPLE_COUNT > 3)
		{
			wBATTERY_VOLTAGE = wBATTERY_VOLTAGE_SUM>>2;
			wBATTERY_VOLTAGE_SUM = 0;
			byBATTERY_VOLTAGE_SAMPLE_COUNT = 0;
		}
		
		wBOOST_VOLTAGE_SUM = wBOOST_VOLTAGE_SUM + ADC1_GetConversionValue();
		byBOOST_VOLTAGE_SAMPLE_COUNT++;
		if(byBOOST_VOLTAGE_SAMPLE_COUNT > 3)
		{
			wBOOST_VOLTAGE = wBOOST_VOLTAGE_SUM>>2;
			wBOOST_VOLTAGE_SUM = 0;
			byBOOST_VOLTAGE_SAMPLE_COUNT = 0;
		}
 }