ADC Device

中文

ADC Device

Open ADC Device

int mr_dev_open(const char *path, int flags);

Parameter	Description
path	Device path
flags	Open device flags
Return Value
`>=0`	Device descriptor
`<0`	Error code

path: ADC device path usually is: adcx, adc1, adc2.
flags: Open device flags, support MR_O_RDONLY.

Note: When using, the ADC device should be opened separately for different tasks according to actual situations, and the appropriate flags should be used for management and permission control to ensure they will not interfere with each other.

Close ADC Device

int mr_dev_close(int desc);

Parameter	Description
desc	Device descriptor
Return Value
`=0`	Close successfully
`<0`	Error code

Note: When closing the device, all channels will be automatically restored to the default state. The channel needs to be reconfigured after reopening(This feature can be turned off).

Control ADC Device

int mr_dev_ioctl(int desc, int cmd, void *args);

Parameter	Description
desc	Device descriptor
cmd	Command code
args	Command parameters
Return Value
`=0`	Set successfully
`<0`	Error code

cmd: Command code, supports the following commands:
- MR_IOC_ADC_SET_CHANNEL: Set channel number.
- MR_IOC_ADC_SET_CHANNEL_CONFIG: Set channel configure.
- MR_IOC_ADC_GET_CHANNEL: Get channel number.
- MR_IOC_ADC_GET_CHANNEL_CONFIG: Get channel configure.

Set/Get Channel Number

Channel number range: 0 ~ 31.

/* Define channel number */
#define CHANNEL_NUMBER                  5

/* Set channel number */  
mr_dev_ioctl(ds, MR_IOC_ADC_SET_CHANNEL, MR_MAKE_LOCAL(int, CHANNEL_NUMBER));

/* Get channel number */
int number;
mr_dev_ioctl(ds, MR_IOC_ADC_GET_CHANNEL, &number);

Independent of ADC interface:

/* Define channel number */
#define CHANNEL_NUMBER                  5

/* Set channel number */
mr_dev_ioctl(ds, MR_IOC_SPOS, MR_MAKE_LOCAL(int, CHANNEL_NUMBER));

/* Get channel number */
int number;
mr_dev_ioctl(ds, MR_IOC_GPOS, &number);

Set/Get Channel Configure

Channel configure:

MR_DISABLE: Disable channel.
MR_ENABLE: Enable channel.

/* Set channel configure */
mr_dev_ioctl(ds, MR_IOC_ADC_SET_CHANNEL_CONFIG, MR_MAKE_LOCAL(int, MR_ENABLE)); 

/* Get channel configure */  
int state;
mr_dev_ioctl(ds, MR_IOC_ADC_GET_CHANNEL_CONFIG, &state);

Independent of ADC interface:

/* Set channel configure */
mr_dev_ioctl(ds, MR_IOC_SCFG, MR_MAKE_LOCAL(int, MR_ENABLE)); 

/* Get channel configure */  
int state;
mr_dev_ioctl(ds, MR_IOC_GCFG, &state);

Read ADC Device Channel Value

ssize_t mr_dev_read(int desc, void *buf, size_t count);

Parameter	Description

desc	Device descriptor
buf	Read data buffer
count	Read data size
Return Value
`>=0`	Read data size
`<0`	Error code

/* Read channel value */
uint32_t data;
int ret = mr_dev_read(ds, &data, sizeof(data));
/* Check if read successfully */
if (ret != sizeof(data))
{
    return ret;  
}

Note: The read data is the raw ADC data. The minimum read unit is uint32_t, that is, 4 bytes each time.

Usage Example:

#include "include/mr_lib.h"

/* Define channel number */
#define CHANNEL_NUMBER                  5

/* Define ADC device descriptor */  
int adc_ds = -1;

void adc_init(void)
{
   int ret = MR_EOK;

   /* Initialize ADC */
   adc_ds = mr_dev_open("adc1", MR_O_RDONLY);
   if (adc_ds < 0)
   {
       mr_printf("ADC1 open failed: %s\r\n", mr_strerror(adc_ds));
       return;
   }
   /* Print ADC descriptor */
   mr_printf("ADC1 desc: %d\r\n", adc_ds);
   /* Set to channel 5 */
   mr_dev_ioctl(adc_ds, MR_IOC_ADC_SET_CHANNEL, MR_MAKE_LOCAL(int, CHANNEL_NUMBER));
   /* Set channel enable */
   ret = mr_dev_ioctl(adc_ds, MR_IOC_ADC_SET_CHANNEL_CONFIG, MR_MAKE_LOCAL(int, MR_ENABLE));
   if (ret < 0)
   {
       mr_printf("Channel5 enable failed: %s\r\n", mr_strerror(ret));
   }
}
/* Export to automatic initialization (APP level) */
MR_INIT_APP_EXPORT(adc_init); 

int main(void)
{
   /* Automatic initialization (adc_init function will be automatically called here) */
   mr_auto_init();

   while(1)
   {
       uint32_t data;
       int ret = mr_dev_read(adc_ds, &data, sizeof(data));
       if (ret != sizeof(data)) 
       {
           mr_printf("Read failed: %s\r\n", mr_strerror(ret));
       }
       mr_printf("ADC value: %d\r\n", data);
       mr_delay_ms(1000);
   }
}

Enable ADC1 channel 5, read the ADC value every second and print it.

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