SystemBase Eddy DK, Руководство программиста

Страница: 118 / 147

Eddy DK Programmer Guide
118
6.8 ADC Function
Eddy CPU provides 4 channels of ADC(Analog Digital Converter).
Eddy DK board has temperature and illumination sensor for testing and the status of the sensors can be checked in
real time with ADC.
Sample program “
Eddy_Apps/test_adc.c ” uses ADC interface so users can refer to this source for developing
programs.
ADCSETCHANNEL
Function Configures whether to use 4 channels of ADC device or not.
Format void ioctl(int fd, ADCSETCHANNEL, int *channel);
Parameter fd Handle to ADC device(“/dev/adc”)
mode Pointer to the buffer that stores channel configuration
Returns None
Notice X X X X X X X X (bits)
| | | |----- channel 1 (temperature sensor)
| | |--------- channel 2 (illumination sensor)
| |------------- channel 3 (future use)
|----------------- channel 4 (future use)
ADCGETVALUE
Function Reads operation status of 4channels of ADC device
Format void ioctl(int fd, ADCGETVALUE, struct adc_struct *channels);
Parameter fd Handle to ADC device(“/dev/adc”)
mode Pointer to the buffer that will store channel operation
status
Returns None
Notice Struct adc_value {
int ch1_value;
int ch2_value;
int ch3_value;
int ch4_value;
};