I think there are none error,but always error?

[ligang]

I add the .c and .h file, but always error? Why?

[Eugene Yu]

Hi ligang,

You need to enable the ADC in sdk_config.h

There are two way to enable ADC on Keil

1. Change the code directly
2. Check checkbox in configuration wizard

For No.1 you need to modify the code in sdk_config.h as below

//==========================================================
// <e> ADC_ENABLED - nrf_drv_adc - Driver for ADC peripheral (nRF51)
//==========================================================
#ifndef ADC_ENABLED
#define ADC_ENABLED 1
#endif

For No.2 Select "Configuration wizard tab" after select sdk_config.h See below picture it is better way for understanding.