ltc2488.h File Reference

#include <stdbool.h>
#include "no_os_spi.h"
#include "no_os_util.h"

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Classes
struct	ltc2488_dev
	Device driver structure. More...
struct	ltc2488_dev_init
	Device driver initialization parameters. More...

Macros
#define	LTC2488_VREF   4.096
#define	LTC2488_CHANNEL_CONV_TIME   150
#define	LTC2488_CHANNEL_EOC_MASK   NO_OS_BIT(23)
#define	LTC2488_CHANNEL_SIGN_BIT_MASK   NO_OS_BIT(21)
#define	LTC2488_CHANNEL_MSB_BIT_MASK   NO_OS_BIT(20)
#define	LTC2488_CHANNEL_MASK_17BITS   NO_OS_GENMASK(16,0)
#define	LTC2488_FS_VOLTAGE   (LTC2488_VREF*0.5)
#define	LTC2488_SINGLE_CH0   0xB0
#define	LTC2488_SINGLE_CH1   0xB8
#define	LTC2488_SINGLE_CH2   0xB1
#define	LTC2488_SINGLE_CH3   0xB9
#define	LTC2488_CHANNEL_CONF_DISABLE   0x80
#define	LTC2488_CHANNEL_CONF_ENABLE   0xA0
#define	LTC2488_INPUT_RANGE(x)
#define	LTC2488_EOC_DETECT(x)    ((x & LTC2488_CHANNEL_EOC_MASK ) ? false : true)
#define	LTC2488_GET_ADC_DATA(x)   ((x >> 4) & LTC2488_CHANNEL_MASK_17BITS)
#define	LTC2488_SIGN_EXTEND_ADC_DATA(x)

Enumerations
enum	input_status {   UNDER_RANGE ,   NEGATIVE_RANGE ,   POSITIVE_RANGE ,   OVER_RANGE }
	Various Input range. More...

Functions
enum input_status	ltc2488_data_process (const uint32_t *adc_code, int32_t *adc_value)
	Extracts the actual 17-Bit ADC value from the ADC code, returns the 32-bit sign extended value along with over/underrange status. The ADC value to be returned has been to limited to +1 the max 17-bit positive value (for over-range) or -1 the minimum 17-bit value (for under-range) to avoid the ADC value being misinterpreted when not in desired range. More...
float	ltc2488_code_to_voltage (const int32_t *adc_data)
	Calculates the voltage corresponding to an adc code, given the reference voltage (in volts). Currently this function only supports the single-ended configuration. More...
int32_t	ltc2488_init (struct ltc2488_dev **device, struct ltc2488_dev_init *init_param)
	Initialize the ltc2488 device structure. More...
int32_t	ltc2488_remove (struct ltc2488_dev *dev)
	Free any resource used by the driver. More...
int32_t	ltc2488_read_write (struct no_os_spi_desc *desc, uint8_t buff_cmd, uint32_t *adc_buff)
	Reads/writes data from/to LTC2488 ADC that accepts a 8 bit configuration and returns a 24 bit result. More...

Macro Definition Documentation

LTC2488_CHANNEL_CONF_DISABLE

#define LTC2488_CHANNEL_CONF_DISABLE   0x80

LTC2488_CHANNEL_CONF_ENABLE

#define LTC2488_CHANNEL_CONF_ENABLE   0xA0

LTC2488_CHANNEL_CONV_TIME

#define LTC2488_CHANNEL_CONV_TIME   150

LTC2488_CHANNEL_EOC_MASK

#define LTC2488_CHANNEL_EOC_MASK   NO_OS_BIT(23)

LTC2488_CHANNEL_MASK_17BITS

#define LTC2488_CHANNEL_MASK_17BITS   NO_OS_GENMASK(16,0)

LTC2488_CHANNEL_MSB_BIT_MASK

#define LTC2488_CHANNEL_MSB_BIT_MASK   NO_OS_BIT(20)

LTC2488_CHANNEL_SIGN_BIT_MASK

#define LTC2488_CHANNEL_SIGN_BIT_MASK   NO_OS_BIT(21)

LTC2488_EOC_DETECT

#define LTC2488_EOC_DETECT

(

x

)

((x & LTC2488_CHANNEL_EOC_MASK ) ? false : true)

LTC2488_FS_VOLTAGE

#define LTC2488_FS_VOLTAGE   (LTC2488_VREF*0.5)

LTC2488_GET_ADC_DATA

#define LTC2488_GET_ADC_DATA

(

x

)

((x >> 4) & LTC2488_CHANNEL_MASK_17BITS)

LTC2488_INPUT_RANGE

#define LTC2488_INPUT_RANGE

(

x

)

Value:

        (enum input_status)(((x) & \
        (LTC2488_CHANNEL_SIGN_BIT_MASK | LTC2488_CHANNEL_MSB_BIT_MASK)) >> 20)

LTC2488_SIGN_EXTEND_ADC_DATA

#define LTC2488_SIGN_EXTEND_ADC_DATA

(

x

)

Value:

        ((x ^(LTC2488_CHANNEL_MSB_BIT_MASK >> 4)) - \
        (LTC2488_CHANNEL_MSB_BIT_MASK >> 4))

LTC2488_SINGLE_CH0

#define LTC2488_SINGLE_CH0   0xB0

LTC2488_SINGLE_CH1

#define LTC2488_SINGLE_CH1   0xB8

LTC2488_SINGLE_CH2

#define LTC2488_SINGLE_CH2   0xB1

LTC2488_SINGLE_CH3

#define LTC2488_SINGLE_CH3   0xB9

LTC2488_VREF

#define LTC2488_VREF   4.096

Enumeration Type Documentation

input_status

enum input_status

Various Input range.

Enumerator
UNDER_RANGE
NEGATIVE_RANGE
POSITIVE_RANGE
OVER_RANGE

Function Documentation

ltc2488_code_to_voltage()

float ltc2488_code_to_voltage

(

const int32_t *

adc_data

)

Calculates the voltage corresponding to an adc code, given the reference voltage (in volts). Currently this function only supports the single-ended configuration.

Parameters

adc_code

- Pointer to Read-Only 24bit ADC output word in 32bit format

Returns

Corresponding Voltage Output

ltc2488_data_process()

enum input_status ltc2488_data_process	(	const uint32_t *	adc_code,
		int32_t *	adc_value
	)

Extracts the actual 17-Bit ADC value from the ADC code, returns the 32-bit sign extended value along with over/underrange status. The ADC value to be returned has been to limited to +1 the max 17-bit positive value (for over-range) or -1 the minimum 17-bit value (for under-range) to avoid the ADC value being misinterpreted when not in desired range.

SPI DATA FORMAT (MSB First): Byte #1 Byte #2

Data Out : !EOC DMY SIG MSB D15 D14 D13 D12 D11 D10 D9 D8 D7 D6 D5 D4 Data In : 1 0 EN SGL OS A2 A1 A0 X X X X X X X X

      Byte #3

Data Out : D3 D2 D1 D0 - - - - Data In : X X X X X X X X

!EOC : End of Conversion Bit (Active Low) DMY : Dummy Bit (Always 0) SIG : Sign Bit (1-data positive, 0-data negative) MSB : Most Significant Bit (Provides under range and over range indication) Dx : Data Bits EN : Enable Bit (0-keep previous mode, 1-change mode) SGL : Enable Single-Ended Bit (0-differential, 1-single-ended) OS : ODD/Sign Bit Sx : Address Select Bit

Command Byte 1 0 EN SGL OS A2 A1 A0 Comments 1 0 0 X X X X X Keep Previous Mode 1 0 1 0 X X X X Differential Mode 1 0 1 1 X X X X Single-Ended Mode

Parameters

adc_code	- Pointer to Read-Only 24bit ADC output word in 32bit format
adc_value	- Pointer to buffer to store the 32 bit sign extended adc value. Under-Range : 0xFFFDFFFF , Over-Range : 0x00020000

Returns

Input range

ltc2488_init()

int32_t ltc2488_init	(	struct ltc2488_dev **	device,
		struct ltc2488_dev_init *	init_param
	)

Initialize the ltc2488 device structure.

Performs memory allocation of the device structure.

Parameters

device	- Pointer to location of device structure to write.
init_param	- Pointer to configuration of the driver.

Returns

ret - return code. Example: FAILURE- Errors Encountered. SUCCESS - No errors encountered.

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ltc2488_read_write()

int32_t ltc2488_read_write	(	struct no_os_spi_desc *	desc,
		uint8_t	adc_cmd,
		uint32_t *	adc_buff
	)

Reads/writes data from/to LTC2488 ADC that accepts a 8 bit configuration and returns a 24 bit result.

Parameters

device	- Pointer to the lcoation of SPI device descriptor.
adc_cmd	- 8 bit adc command word.
adc_buff	- The buffer to receive 24 bit output data word.

Returns

Status of SPI transaction

ltc2488_remove()

int32_t ltc2488_remove

(

struct ltc2488_dev *

dev

)

Free any resource used by the driver.

Parameters

dev	- The device structure.

Returns

ret - return code. Example: -EIO - SPI communication error. SUCCESS - No errors encountered.

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