Linduino  1.3.0
Linear Technology Arduino-Compatible Demonstration Board

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.

All rights reserved.

Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met:

  • Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer.
  • Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution.
  • Neither the name of Analog Devices, Inc. nor the names of its contributors may be used to endorse or promote products derived from this software without specific prior written permission.
  • The use of this software may or may not infringe the patent rights of one or more patent holders. This license does not release you from the requirement that you obtain separate licenses from these patent holders to use this software.
  • Use of the software either in source or binary form, must be run on or directly connected to an Analog Devices Inc. component.

THIS SOFTWARE IS PROVIDED BY ANALOG DEVICES "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, NON-INFRINGEMENT, MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL ANALOG DEVICES BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, INTELLECTUAL PROPERTY RIGHTS, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

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_codeCode read from ADC
LTC2305_vrefLSB 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_addressI2C address of device
adc_commandADC command / address bits
ptr_adc_codeReturns 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.