ADC problem

嗨

im trying to read a voltage output from a voltage devider ( 3v to be precise), and i managed to understand some parts about the adc reading

using the sdk 6.0.14 i wrote this code based on the batt example in the peripheral examples

/ /在periph_setup.h

#define ADC_PORT GPIO_PORT_0
#define ADC_PIN GPIO_PIN_1

uint32_t adc_get_voltage_sample(void);

GPIO_ConfigurePin(ADC_PORT,ADC_PIN,INPUT,PID_ADC,false); // in set_pad_functions

//in periph_setup.c

uint32_t adc_get_voltage_sample(void)
{
uint32_t adc_sample;
adc_config_t cfg =
{
.mode = ADC_INPUT_MODE_SINGLE_ENDED,
.sign = true,
.attn = true
};
adc_init(&cfg);

adc_set_se_input(ADC_INPUT_SE_P0_1);
adc_sample = adc_get_sample();

adc_disable();
return adc_sample;

};

and i called this function in the main.c trying to get the value through teraterm

printf_byte_dec(UART, adc_get_voltage_sample());

the value i get is 24-25 ... i suppose if the code is correct this value is wrong ... thank you