ADc CC2541 pull up activate

hello people,

 in my proyect i hav a a adc on channel 07, but this pin have active the púll-up and i dont hace who desactive the pull up the basic code is:

 HalAdcInit();
uint8 Galv[1];
 
  HalAdcSetReference( HAL_ADC_REF_AVDD );

   Galv[0]= HalAdcRead (HAL_ADC_CHANNEL_7, HAL_ADC_RESOLUTION_8);
  Galv_SetParameter(SENSOR_DATA, GALVANIC_DATA_LEN, Galv);
 

any have idea?

thx people