With the code below I open the adc, start reading adc and after than I close the adc.
At the first and the second call of my adc calls I get the correct measured values. But on third time I cannot open the adc driver.
Than the function “_adc_open” in kernel-file adc.c return me the value “ADC_ERROR_OPENED” (cannot open more than one instance of ADC driver).
Does anyone have an idea what is going wrong here? Do I have a mistake by closing the driver?
Thank you for replay.
const ADC_INIT_CHANNEL_STRUCT adc_channel_param ={ ADC0_SOURCE_AD0, /* physical ADC channel */ ADC_CHANNEL_START_TRIGGERED, 1, /* number of samples in one run sequence */ 0, /* time offset from trigger point in us */ 300000, /* period in us (= 0.3 sec) */ 0x10000, /* scale range of result (not used now) */ 1, /* circular buffer size (sample count) */ ADC_PDB_TRIGGER,/* logical trigger ID that starts this ADC channel */};uint32_t adc_get_raw(void){ ADC_RESULT_STRUCT adc_data; MQX_FILE_PTR adc_fp = NULL; MQX_FILE_PTR channel_input_fp = NULL; //!___open__________________________________________________________________ printf("Opening %s ...", MY_ADC); adc_fp = fopen(MY_ADC, (const char*)&adc_init_sruct); if(adc_fp != NULL) printf("done\n"); else { printf("failed\n"); return 0; } printf("Opening channel ..."); channel_input_fp= fopen(MY_ADC "channel",(const char*)&adc_channel_param); if(channel_input_fp != NULL) printf("done\n"); else { printf("failed\n"); return 0; } _time_delay(500); //!___start_measurement_____________________________________________________ ioctl(adc_fp, ADC_IOCTL_FIRE_TRIGGER, (pointer) MY_TRIGGER); //!___measure_______________________________________________________________ if (read(channel_input_fp, &adc_data, sizeof(adc_data) )) { printf("ADC: %4d \n", adc_data.result); } if (IO_OK == ioctl (channel_input_fp, ADC_IOCTL_STOP_CHANNELS, NULL)) { printf("stopped\n"); } else { printf("failed\n"); } //!___close_________________________________________________________________ //! close all ADC channels printf("Close ADC channel..."); if ( fclose(channel_input_fp) == MQX_OK ) printf("ok\n"); printf("Close ADC driver..."); if ( fclose(adc_fp) == MQX_OK ) printf("ok\n"); else if ( fclose(adc_fp) == ADC_ERROR_NONEMPTY ) printf("--> ADC_ERROR_NONEMPTY --> failed\n"); else printf("failed\n"); return adc_data.result;}
This is the debug output:
Opening adc0: ...done
Opening channel ...done
ADC: 2049
stopped
Close ADC channel...ok
Close ADC driver...ok
Opening adc0: ...done
Opening channel ...done
ADC: 2034
stopped
Close ADC channel...ok
Close ADC driver...ok
Opening adc0: ...done
Opening channel ...failed
Opening adc0: ...failed
....
