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LTC2305.h File Reference
Analog-to-Digital Converters (ADC) » LTC2305: 2-channel, 12-Bit SAR ADC with I2C interface

LTC2305: 8-channel, 12-Bit SAR ADC with I2C interface. More...

## Detailed Description

LTC2305: 8-channel, 12-Bit SAR ADC with I2C interface.

    The LTC2305 is a low noise, low power, 8-channel, 12-bit successive
    approximation ADC with an I2C compatible serial interface. This ADC includes an
    internal reference and a fully differential sample-and-hold circuit to reduce
    common mode noise. The LTC2305 operates from an internal clock to achieve a fast
    1.3 microsecond conversion time.

    The LTC2305 operates from a single 5V supply and draws just 300 microamps at a
    throughput rate of 1ksps. The ADC enters nap mode when not converting, reducing
    the power dissipation.

    I2C DATA FORMAT (MSB First):

           Byte #1                             Byte #2
    START  SA6 SA5 SA4 SA3 SA2 SA1 SA0 W SACK  SD OS S1 S0 UNI SLP X X SACK

                 Byte #3                             Byte #4                             Byte #5
    Repeat Start SA6 SA5 SA4 SA3 SA2 SA1 SA0 R SACK  D11 D10 D9  D8  D7  D6  D5 D4 MACK  D3 D2 D1 D0 X  X  X  X  MNACK  STOP

    SACK  : Slave Acknowledge
    MACK  : Master Acknowledge
    MNACK : Master Not Acknowledge
    SD    : Single, Differential# Bit
    OS    : ODD, Sign# Bit
    Sx    : Address Select Bit
    COM   : CH7/COM Configuration Bit
    UNI   : Unipolar, Bipolar# Bit
    SLP   : Sleep Mode Bit
    Dx    : Data Bits
    X     : Don't care

    Example Code:

    Read Channel 0 in Single-Ended Unipolar mode

        adc_command = LTC2305_CH0 | LTC2305_UNIPOLAR_MODE;                  // Build ADC command for channel 0

        ack |= LTC2305_read(LTC2305_I2C_ADDRESS, adc_command, &adc_code);   // Throws out last reading
        ack |= LTC2305_read(LTC2305_I2C_ADDRESS, adc_command, &adc_code);   // Obtains the current reading and stores to adc_code variable

        // Convert adc_code to voltage
        adc_voltage = LTC2305_unipolar_code_to_voltage(adc_code, LTC2305_lsb, LTC2305_offset_code);

http://www.linear.com/product/LTC2305

http://www.linear.com/product/LTC2305#demoboards

Copyright 2018(c) Analog Devices, Inc.

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Header for LTC2305: 8-channel, 12-Bit SAR ADC with I2C interface

Definition in file LTC2305.h.

Go to the source code of this file.

## Functions
int8_t | LTC2305_read (uint8_t i2c_address, uint8_t adc_command, uint16_t *ptr_adc_code)
| Reads 12-bit code from LTC2305, programs channel and mode for next conversion. More...
float | LTC2305_code_to_voltage (uint16_t adc_code, float LTC2305_vref, uint8_t uni_bipolar)
| Calculates the LTC2305 input voltage. More...

## Macros
I2C addresses
Un-comment the address corresponding to the LTC2305's address
#define | LTC2305_I2C_ADDRESS 0x08
Single-Ended Channel Configuration
#define | LTC2305_CH0 0xC0
#define | LTC2305_CH1 0x80
LTC2305 Configuration Bits
#define | LTC2305_SLEEP_MODE 0x04
#define | LTC2305_EXIT_SLEEP_MODE 0x00
#define | LTC2305_UNIPOLAR_MODE 0x08
#define | LTC2305_BIPOLAR_MODE 0x00
#define | LTC2305_SINGLE_ENDED_MODE 0x80
#define | LTC2305_DIFFERENTIAL_MODE 0x00
#define | LTC2305_P0_N1 0x00
#define | LTC2305_P1_N0 0x40
#define | LTC2301 1
#define | LTC2305 0

## Function Documentation

## ◆ LTC2305_code_to_voltage()

float LTC2305_code_to_voltage | ( | uint16_t | adc_code,
|  | float | LTC2305_vref,
|  | uint8_t | uni_bipolar
| ) |  |

Calculates the LTC2305 input voltage.

Returns
  Calculated voltage

Parameters

  adc_code | Code read from ADC
  LTC2305_vref | LSB value (volts)

Definition at line 103 of file LTC2305.cpp.

## ◆ LTC2305_read()

int8_t LTC2305_read | ( | uint8_t | i2c_address,
|  | uint8_t | adc_command,
|  | uint16_t * | ptr_adc_code
| ) |  |

Reads 12-bit code from LTC2305, programs channel and mode for next conversion.

Returns
  Returns the state of the acknowledge bit after the I2C address write. 0=acknowledge, 1=no acknowledge.

Parameters

  i2c_address | I2C address of device
  adc_command | ADC command / address bits
  ptr_adc_code | Returns code read from ADC

Definition at line 86 of file LTC2305.cpp.

## Macro Definition Documentation

## ◆ LTC2301

#define LTC2301 1

Definition at line 137 of file LTC2305.h.

## ◆ LTC2305

#define LTC2305 0

Definition at line 138 of file LTC2305.h.

## ◆ LTC2305_BIPOLAR_MODE

#define LTC2305_BIPOLAR_MODE 0x00

Definition at line 131 of file LTC2305.h.

## ◆ LTC2305_CH0

#define LTC2305_CH0 0xC0

Definition at line 120 of file LTC2305.h.

## ◆ LTC2305_CH1

#define LTC2305_CH1 0x80

Definition at line 121 of file LTC2305.h.

## ◆ LTC2305_DIFFERENTIAL_MODE

#define LTC2305_DIFFERENTIAL_MODE 0x00

Definition at line 133 of file LTC2305.h.

## ◆ LTC2305_EXIT_SLEEP_MODE

#define LTC2305_EXIT_SLEEP_MODE 0x00

Definition at line 129 of file LTC2305.h.

## ◆ LTC2305_I2C_ADDRESS

#define LTC2305_I2C_ADDRESS 0x08

Definition at line 106 of file LTC2305.h.

## ◆ LTC2305_P0_N1

#define LTC2305_P0_N1 0x00

Definition at line 134 of file LTC2305.h.

## ◆ LTC2305_P1_N0

#define LTC2305_P1_N0 0x40

Definition at line 135 of file LTC2305.h.

## ◆ LTC2305_SINGLE_ENDED_MODE

#define LTC2305_SINGLE_ENDED_MODE 0x80

Definition at line 132 of file LTC2305.h.

## ◆ LTC2305_SLEEP_MODE

#define LTC2305_SLEEP_MODE 0x04

Definition at line 128 of file LTC2305.h.

## ◆ LTC2305_UNIPOLAR_MODE

#define LTC2305_UNIPOLAR_MODE 0x08

Definition at line 130 of file LTC2305.h.