This library is itended for microcontroller applications using Teensy (3.x to 4.x), ESP's, and Arduinos where additional analog inputs or higher resulution inputs are needed. This library supports all the features offered by the LTC1867 such as reading an input channel in single or differential mode, using GND or CH7 as the common pin, and putting the analog to digital converter to sleep to save power between infrequent reads. See the .h file for all the constants to set channels and options.
Perfomance is as follows
| Data | LTC1867 | Teensy 3.2 | Teensy 4.0 | ESP32 |
|---|---|---|---|---|
| analogRead | 17 uS | 6 uS | 17 uS uS | 243 uS |
Implentation of this library is straightforward
- include the library
#include "LTC1867.h" 2. create an object instance(s)
LTC1867 MyADC(CS_PIN); 5. initialize the object(s)
MyADC.init(); // object attempts to return true if successful 7. call object.analogRead(channel)
uint16_t thing = MyADC.analogRead(CH0);
Optionally you can 1. change the VRef (see the data sheet for how to override the internal voltage regulator
object.setVRef(value);
-
Automatically convert the output to a voltage
object.getVolts(channel); -
Automatically read and average several data points
object.analogReadAveraging(count) where count can be 1 to 1000
Typical wiring, note the use of a buffer to shift the output of MISO (DO) to be compatible with 3v3 MCU's
Noise comparison from the LTC1867 (16 bit), a Cortex M4 (16 bit) and an ESP32 (12 bit as 16 bit is not available). Note that no input filtering was used in this test. shown are 1 average per point and sandwitched between and upper and lower guardrails. The ADC noise performace is improvement over the cortex M4 chip, the ESP32 suffers.
Noise from from the LTC1867 (16 bit), a Cortex M4 (16 bit) using analogRead() and analogReadAveraging(). Note that no input filtering was used in this test. Shown are 10 averages per point and sandwitched between and upper and lower guardrail.
