ltc2488.h

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/***************************************************************************
 *   @file   ltc2488.h
 *   @brief  Header file for the LTC2488 Driver
 *
********************************************************************************
 * Copyright (c) 2021-22 Analog Devices, Inc.
 *
 * All rights reserved.
 *
 * This software is proprietary to Analog Devices, Inc. and its licensors.
 * By using this software you agree to the terms of the associated
 * Analog Devices Software License Agreement.
 *
*****************************************************************************/
 
#ifndef LTC2488_H
#define LTC2488_H
 
/******************************************************************************/
/***************************** Include Files **********************************/
/******************************************************************************/
 
#include <stdbool.h>
#include "no_os_spi.h"
#include "no_os_util.h"
 
/******************************************************************************/
/********************** Macros and Constants Definitions **********************/
 
#define LTC2488_VREF                          4.096  // Reference Volatage 
#define LTC2488_CHANNEL_CONV_TIME               150  // Timeout in millisends
#define LTC2488_CHANNEL_EOC_MASK             NO_OS_BIT(23) // EOC bit mask
#define LTC2488_CHANNEL_SIGN_BIT_MASK        NO_OS_BIT(21) // SIGN bit mask
#define LTC2488_CHANNEL_MSB_BIT_MASK         NO_OS_BIT(20) // MSB bit mask
#define LTC2488_CHANNEL_MASK_17BITS    NO_OS_GENMASK(16,0) // 16 bit data + 1 bit sign
#define LTC2488_FS_VOLTAGE        (LTC2488_VREF*0.5) // Full Scale Range
 
/* Single-Ended Channel Configuration
* Channel selection for all Single-Ended Inputs
*
* MUX ADDRESS              CHANNEL SELECTION
* SGL  OS   A2   A1   A0 | 0    1    2    3    COM
* 1    0    0    0    0  | IN+  -    -    -    IN-
* 1    0    0    0    1  | -    -    IN+  -    IN-
* 1    1    0    0    0  | -    IN+  -    -    IN-
* 1    1    0    0    1  | -    -    -    IN+  IN-
*/
#define LTC2488_SINGLE_CH0            0xB0
#define LTC2488_SINGLE_CH1            0xB8
#define LTC2488_SINGLE_CH2            0xB1
#define LTC2488_SINGLE_CH3            0xB9
 
// Channel Configuration Enable/Disable Bits
#define LTC2488_CHANNEL_CONF_DISABLE         0x80
#define LTC2488_CHANNEL_CONF_ENABLE          0xA0
 
// Masks the read only adc code to extract only the status bits.
#define LTC2488_INPUT_RANGE(x)  \
        (enum input_status)(((x) & \
        (LTC2488_CHANNEL_SIGN_BIT_MASK | LTC2488_CHANNEL_MSB_BIT_MASK)) >> 20)
 
// If End Of Conversion status detected returns true
#define LTC2488_EOC_DETECT(x)  \
        ((x & LTC2488_CHANNEL_EOC_MASK ) ? false : true)
 
// Masks the read-only adc code to extract only 17 bits conversion result
#define LTC2488_GET_ADC_DATA(x)     ((x >> 4) & LTC2488_CHANNEL_MASK_17BITS)
 
// Signs extends the 17 bit value to 32 bit value
#define LTC2488_SIGN_EXTEND_ADC_DATA(x)  \
        ((x ^(LTC2488_CHANNEL_MSB_BIT_MASK >> 4)) - \
        (LTC2488_CHANNEL_MSB_BIT_MASK >> 4))
 
enum input_status {
    UNDER_RANGE,
    NEGATIVE_RANGE,
    POSITIVE_RANGE,
    OVER_RANGE
};
 
struct ltc2488_dev {
    // SPI descriptor
    struct no_os_spi_desc *spi_desc;
};
 
struct ltc2488_dev_init {
    // SPI initialization parameters
    struct no_os_spi_init_param spi_init ;
};
 
/******************************************************************************/
/********************** Function Declarations *********************************/
 
enum input_status ltc2488_data_process(const uint32_t *adc_code,
                       int32_t *adc_value);
 
float ltc2488_code_to_voltage(const int32_t *adc_data);
 
int32_t ltc2488_init(struct ltc2488_dev **device,
             struct ltc2488_dev_init *init_param);
 
int32_t ltc2488_remove(struct ltc2488_dev *dev);
 
int32_t ltc2488_read_write(struct no_os_spi_desc *desc,
               uint8_t buff_cmd,
               uint32_t *adc_buff);
 
#endif