driver_afs01.c

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#include "driver_afs01.h"

#define CHIP_NAME                 "ASAIR AFS01"        
#define MANUFACTURER_NAME         "ASAIR"              
#define SUPPLY_VOLTAGE_MIN        4.75f                
#define SUPPLY_VOLTAGE_MAX        5.25f                
#define MAX_CURRENT               10.0f                
#define TEMPERATURE_MIN           25.0f                
#define TEMPERATURE_MAX           50.0f                
#define DRIVER_VERSION            1000                 

#define AFS01_ADDRESS        0x80        

#define AFS01_COMMAND_READ_DATA        0x1000U        
#define AFS01_COMMAND_READ_ID          0x31AEU        

static uint8_t a_afs01_read(afs01_handle_t *handle, uint16_t reg, uint8_t *data, uint16_t len)
{
    if (handle->iic_read_address16(AFS01_ADDRESS, reg, data, len) != 0)        /* read the register */
    {
        return 1;                                                              /* return error */
    }
    
    return 0;                                                                  /* success return 0 */
}

static uint8_t a_afs01_crc(uint8_t *data, uint16_t len)
{
    const uint8_t POLYNOMIAL = 0x31;
    uint8_t crc = 0x00;
    uint16_t i, j;
  
    for (j = len; j != 0; --j)                                              /* length-- */
    {
        crc ^= *data++;                                                     /* xor */
        for (i = 8; i != 0; --i)                                            /* 8 times */
        {
            crc = (crc & 0x80) ? (crc << 1) ^ POLYNOMIAL : (crc << 1);      /* calculate crc */
        }
    }
  
    return crc;                                                             /* return crc */
}

uint8_t afs01_init(afs01_handle_t *handle)
{
    if (handle == NULL)                                                      /* check handle */
    {
        return 2;                                                            /* return error */
    }
    if (handle->debug_print == NULL)                                         /* check debug_print */
    {
        return 3;                                                            /* return error */
    }
    if (handle->iic_init == NULL)                                            /* check iic_init */
    {
        handle->debug_print("afs01: iic_init is null.\n");                   /* iic_init is null */
       
        return 3;                                                            /* return error */
    }
    if (handle->iic_deinit == NULL)                                          /* check iic_deinit */
    {
        handle->debug_print("afs01: iic_deinit is null.\n");                 /* iic_deinit is null */
       
        return 3;                                                            /* return error */
    }
    if (handle->iic_read_address16 == NULL)                                  /* check iic_read_address16 */
    {
        handle->debug_print("afs01: iic_read_address16 is null.\n");         /* iic_read_address16 is null */
       
        return 3;                                                            /* return error */
    }
    if (handle->delay_ms == NULL)                                            /* check delay_ms */
    {
        handle->debug_print("afs01: delay_ms is null.\n");                   /* delay_ms is null */
       
        return 3;                                                            /* return error */
    }
 
    if (handle->iic_init() != 0)                                             /* iic init */
    {
        handle->debug_print("afs01: iic init failed.\n");                    /* iic init failed */
       
        return 1;                                                            /* return error */
    }
    handle->inited = 1;                                                      /* flag finish initialization */
 
    return 0;                                                                /* success return 0 */
}

uint8_t afs01_deinit(afs01_handle_t *handle)
{
    if (handle == NULL)                                            /* check handle */
    {
        return 2;                                                  /* return error */
    }
    if (handle->inited != 1)                                       /* check handle initialization */
    {
        return 3;                                                  /* return error */
    }
    
    if (handle->iic_deinit() != 0)                                 /* iic deinit */
    {
        handle->debug_print("afs01: iic deinit failed.\n");        /* iic deinit failed */
        
        return 1;                                                  /* return error */
    }   
    handle->inited = 0;                                            /* flag close */
    
    return 0;                                                      /* success return 0 */
}

uint8_t afs01_read(afs01_handle_t *handle, uint16_t *raw, float *sccm)
{
    uint8_t res;
    uint8_t buf[3];
    
    if (handle == NULL)                                                 /* check handle */
    {
        return 2;                                                       /* return error */
    }
    if (handle->inited != 1)                                            /* check handle initialization */
    {
        return 3;                                                       /* return error */
    }
    
    res = a_afs01_read(handle, AFS01_COMMAND_READ_DATA, buf, 3);        /* read data */
    if (res != 0)                                                       /* check the result */
    {
        handle->debug_print("afs01: read failed.\n");                   /* read failed */
       
        return 1;                                                       /* return error */
    }
    if (a_afs01_crc(buf, 2) != buf[2])                                  /* check crc */
    {
        handle->debug_print("afs01: crc error.\n");                     /* crc error */
       
        return 4;                                                       /* return error */
    }
    *raw = (uint16_t)(((uint16_t)buf[0]) << 8) | buf[1];                /* set raw data */
    *sccm = ((float)(*raw) - 32000.0f) / 140.0f;                        /* set sccm */
    
    return 0;                                                           /* success return 0 */
}

uint8_t afs01_get_chip_id(afs01_handle_t *handle, uint8_t id[4])
{
    uint8_t res;
    uint8_t buf[6];
    
    if (handle == NULL)                                                 /* check handle */
    {
        return 2;                                                       /* return error */
    }
    if (handle->inited != 1)                                            /* check handle initialization */
    {
        return 3;                                                       /* return error */
    }
    
    res = a_afs01_read(handle, AFS01_COMMAND_READ_ID, buf, 6);          /* read id */
    if (res != 0)                                                       /* check the result */
    {
        handle->debug_print("afs01: read id failed.\n");                /* read id failed */
       
        return 1;                                                       /* return error */
    }
    if (a_afs01_crc(buf, 2) != buf[2])                                  /* check crc */
    {
        handle->debug_print("afs01: crc error.\n");                     /* crc error */
       
        return 4;                                                       /* return error */
    }
    if (a_afs01_crc(buf + 3, 2) != buf[5])                              /* check crc */
    {
        handle->debug_print("afs01: crc error.\n");                     /* crc error */
       
        return 4;                                                       /* return error */
    }
    id[0] = buf[0];                                                     /* set id part 0 */
    id[1] = buf[1];                                                     /* set id part 1 */
    id[2] = buf[3];                                                     /* set id part 2 */
    id[3] = buf[4];                                                     /* set id part 3 */
    
    return 0;                                                           /* success return 0 */
}

uint8_t si7021_get_reg(afs01_handle_t *handle, uint16_t reg, uint8_t *buf, uint16_t len)
{
    if (handle == NULL)                                  /* check handle */
    {
        return 2;                                        /* return error */
    }
    if (handle->inited != 1)                             /* check handle initialization */
    {
        return 3;                                        /* return error */
    } 
    
    if (a_afs01_read(handle, reg, buf, len) != 0)        /* read data */
    {
        return 1;                                        /* return error */
    }
    
    return 0;                                            /* success return 0 */
}

uint8_t afs01_info(afs01_info_t *info)
{
    if (info == NULL)                                               /* check handle */
    {
        return 2;                                                   /* return error */
    }
    
    memset(info, 0, sizeof(afs01_info_t));                          /* initialize afs01 info structure */
    strncpy(info->chip_name, CHIP_NAME, 32);                        /* copy chip name */
    strncpy(info->manufacturer_name, MANUFACTURER_NAME, 32);        /* copy manufacturer name */
    strncpy(info->interface, "IIC", 8);                             /* copy interface name */
    info->supply_voltage_min_v = SUPPLY_VOLTAGE_MIN;                /* set minimal supply voltage */
    info->supply_voltage_max_v = SUPPLY_VOLTAGE_MAX;                /* set maximum supply voltage */
    info->max_current_ma = MAX_CURRENT;                             /* set maximum current */
    info->temperature_max = TEMPERATURE_MAX;                        /* set minimal temperature */
    info->temperature_min = TEMPERATURE_MIN;                        /* set maximum temperature */
    info->driver_version = DRIVER_VERSION;                          /* set driver version */
    
    return 0;                                                       /* success return 0 */
}