Linduino  1.3.0
Linear Technology Arduino-Compatible Demonstration Board

LTC2485: 24-Bit Delta Sigma ADC with Easy Drive Input Current Cancellation and I2C Interface. More...

Detailed Description

LTC2485: 24-Bit Delta Sigma ADC with Easy Drive Input Current Cancellation and I2C Interface.

The LTC2485 combines a 24-bit plus sign No Latency Delta Sigma analog-to-digital
converter with patented Easy Drive technology and I2C digital interface. The
patented sampling scheme eliminates dynamic input current errors and the
shortcomings of on-chip buffering through automatic cancellation of differential
input current. This allows large external source impedances and input signals,
with rail-to-rail input range to be directly digitized while maintaining
exceptional DC accuracy.

Example Code:

Read input with 1X speed mode and rejection frequency of 60Hz

    adc_command = LTC2485_R60 | LTC2485_SPEED_1X;                   // Set to 1X mode with 60hz rejection
    ack |= LTC2485_read(i2c_address, adc_command, &adc_code);       // Throws out last reading
    ack |= LTC2485_read(i2c_address, adc_command, &adc_code);       // Obtains the current reading and stores to adc_code variable

http://www.linear.com/product/LTC2485

http://www.linear.com/product/LTC2485#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 LTC2485: 24-Bit Delta Sigma ADC with Easy Drive Input Current Cancellation and I2C Interface

Definition in file LTC2485.h.

Go to the source code of this file.

Functions

int8_t LTC2485_read (uint8_t i2c_address, uint8_t adc_command, int32_t *adc_code, uint16_t eoc_timeout)
 Reads from LTC2485 ADC that accepts an 8 bit configuration and returns a 24 bit result. More...
 

Macros

I2C_Addresses
#define LTC2485_I2C_GLOBAL_ADDRESS   0b1110111
 I2C address of the LTC2485. More...
 
Mode Configuration

See Table 1 of datasheet.

#define LTC2485_SPEED_1X   0x00
 
#define LTC2485_SPEED_2X   0x01
 
#define LTC2485_INTERNAL_TEMP   0x08
 
#define LTC2485_R50   0x02
 
#define LTC2485_R60   0x04
 
#define LTC2485_R50_R60   0x00
 

Function Documentation

◆ LTC2485_read()

int8_t LTC2485_read ( uint8_t  i2c_address,
uint8_t  adc_command,
int32_t *  adc_code,
uint16_t  eoc_timeout 
)

Reads from LTC2485 ADC that accepts an 8 bit configuration and returns a 24 bit result.

Returns
Returns the state of the acknowledge bit after the I2C address write. 0=acknowledge, 1=no acknowledge.
Parameters
i2c_addressI2C address (7-bit format) for part
adc_commandCommand byte written to LTC2485. Example: (LTC2485_R60 | LTC2485_SPEED_2X)
adc_codeConversion code read from LTC2485. The LTC2485's 32-bit code is converted to 24-bits inside this function.
eoc_timeoutTimeout in ms

Definition at line 70 of file LTC2485.cpp.

Macro Definition Documentation

◆ LTC2485_I2C_GLOBAL_ADDRESS

#define LTC2485_I2C_GLOBAL_ADDRESS   0b1110111

I2C address of the LTC2485.

Configured by tying the CA1 and CA0 pins high, low, or left floating. See Table 4 of datasheet. Uncomment LTC2485_I2C_ADDRESS to match demo board configuration. LTC2485 Global I2C Address.

Definition at line 90 of file LTC2485.h.

◆ LTC2485_INTERNAL_TEMP

#define LTC2485_INTERNAL_TEMP   0x08

Definition at line 99 of file LTC2485.h.

◆ LTC2485_R50

#define LTC2485_R50   0x02

Definition at line 102 of file LTC2485.h.

◆ LTC2485_R50_R60

#define LTC2485_R50_R60   0x00

Definition at line 104 of file LTC2485.h.

◆ LTC2485_R60

#define LTC2485_R60   0x04

Definition at line 103 of file LTC2485.h.

◆ LTC2485_SPEED_1X

#define LTC2485_SPEED_1X   0x00

Definition at line 97 of file LTC2485.h.

◆ LTC2485_SPEED_2X

#define LTC2485_SPEED_2X   0x01

Definition at line 98 of file LTC2485.h.