Since | Origin / Contributor | Maintainer | Source |
---|---|---|---|
2017-04-24 | fetchbot | fetchbot | ads1115.c |
This module provides access to the ADS1115 (16-Bit) and ADS1015 (12-Bit) analog-to-digital converters. Other chips from the same family (ADS1113, ADS1114, ADS1013 and ADS1014) are likely to work. Missing hardware features will be silently ignored.
This module supports multiple devices connected to I²C bus. The devices of different types can be mixed. The addressing of ADS family allows for maximum of 4 devices connected to the same I²C bus.
!!! caution
The **ABSOLUTE MAXIMUM RATINGS** for all analog inputs are `–0.3V to VDD+0.3V` referred to GND.
Registers ADS1115 (ADS1113, ADS1114) device.
ads1115.ADS1115(I2C_ID, I2C_ADDR)
I2C_ID
- always 0ADDRESS
- I²C address of a device
ads1115.ADDR_GND
ads1115.ADDR_VDD
ads1115.ADDR_SDA
ads1115.ADDR_SCL
Registered device
object
local id, sda, scl = 0, 6, 5
i2c.setup(id, sda, scl, i2c.SLOW)
ads1115.reset()
adc1 = ads1115.ads1115(id, ads1115.ADDR_GND)
Registers ADS1015 (ADS1013, ADS1014) device.
ads1115.ads1015(I2C_ID, I2C_ADDR)
I2C_ID
- always 0ADDRESS
- I²C address of a device
ads1115.ADDR_GND
ads1115.ADDR_VDD
ads1115.ADDR_SDA
ads1115.ADDR_SCL
Registered device
object
local id, sda, scl = 0, 6, 5
i2c.setup(id, sda, scl, i2c.SLOW)
ads1115.reset()
adc1 = ads1115.ads1015(id, ads1115.ADDR_VDD)
adc2 = ads1115.ads1115(id, ads1115.ADDR_SDA)
Reset all devices connected to I²C interface.
ads1115.reset()
none
nil
local id, alert_pin, sda, scl = 0, 7, 6, 5
i2c.setup(id, sda, scl, i2c.SLOW)
ads1115.reset()
Gets the result stored in the register of a previously issued conversion, e.g. in continuous mode or with a conversion ready interrupt.
volt, volt_dec, raw, sign = device:read()
none
volt
voltage in mV (see note below)volt_dec
voltage decimal in uV (see note below)adc
raw adc register valuesign
sign of the result (see note below)!!! note
If using float firmware then `volt` is a floating point number, `volt_dec` and `sign` are nil. On an integer firmware, the final value has to be concatenated from `volt`, `volt_dec` and `sign`. On integer firmware `volt` and `volt_dec` are always positive, sign can be `-1`, `0`, `1`.
local id, alert_pin, sda, scl = 0, 7, 6, 5
i2c.setup(id, sda, scl, i2c.SLOW)
ads1115.reset()
adc1 = ads1115.ads1115(id, ads1115.ADDR_GND)
-- continuous mode
adc1:setting(ads1115.GAIN_6_144V, ads1115.DR_128SPS, ads1115.SINGLE_0, ads1115.CONTINUOUS)
-- read adc result with read()
volt, volt_dec, adc, sign = ads1:read()
print(volt, volt_dec, adc, sign)
-- comparator
adc1:setting(ads1115.GAIN_6_144V, ads1115.DR_128SPS, ads1115.SINGLE_0, ads1115.CONTINUOUS, ads1115.COMP_1CONV, 1000, 2000)
local function comparator(level, when)
-- read adc result with read() when threshold reached
gpio.trig(alert_pin)
volt, volt_dec, adc, sign = ads1:read()
print(volt, volt_dec, adc, sign)
end
gpio.mode(alert_pin, gpio.INT)
gpio.trig(alert_pin, "both", comparator)
-- read adc result with read()
volt, volt_dec, adc, sign = ads1115:read()
print(volt, volt_dec, adc, sing)
-- format value in int build
if sign then
-- int build
print(string.format("%s%d.%03d mV", sign >= 0 and "+" or "-", volt, volt_dec))
else
-- float build
-- just use V as it is
end
Configuration settings for the ADC.
device:setting(GAIN, SAMPLES, CHANNEL, MODE[, CONVERSION_RDY][, COMPARATOR, THRESHOLD_LOW, THRESHOLD_HI[,COMP_MODE]])
GAIN
Programmable gain amplifier
ads1115.GAIN_6_144V
2/3x Gainads1115.GAIN_4_096V
1x Gainads1115.GAIN_2_048V
2x Gainads1115.GAIN_1_024V
4x Gainads1115.GAIN_0_512V
8x Gainads1115.GAIN_0_256V
16x GainSAMPLES
Data rate in samples per second
ads1115.DR_8SPS
ADS1115 onlyads1115.DR_16SPS
ADS1115 onlyads1115.DR_32SPS
ADS1115 onlyads1115.DR_64SPS
ADS1115 onlyads1115.DR_128SPS
ads1115.DR_250SPS
ads1115.DR_475SPS
ADS1115 onlyads1115.DR_490SPS
ADS1015 onlyads1115.DR_860SPS
ADS1115 onlyads1115.DR_920SPS
ADS1015 onlyads1115.DR_1600SPS
ADS1015 onlyads1115.DR_2400SPS
ADS1015 onlyads1115.DR_3300SPS
ADS1015 onlyCHANNEL
Input multiplexer for single-ended or differential measurement
ads1115.SINGLE_0
channel 0 to GNDads1115.SINGLE_1
channel 1 to GNDads1115.SINGLE_2
channel 2 to GNDads1115.SINGLE_3
channel 3 to GNDads1115.DIFF_0_1
channel 0 to 1ads1115.DIFF_0_3
channel 0 to 3ads1115.DIFF_1_3
channel 1 to 3ads1115.DIFF_2_3
channel 2 to 3MODE
Device operating mode
ads1115.SINGLE_SHOT
single-shot modeads1115.CONTINUOUS
continuous modeCONVERSION_RDY
Number of conversions after conversion ready asserts (optional)
ads1115.CONV_RDY_1
ads1115.CONV_RDY_2
ads1115.CONV_RDY_4
COMPARATOR
Number of conversions after comparator asserts (optional)
ads1115.COMP_1CONV
ads1115.COMP_2CONV
ads1115.COMP_4CONV
THRESHOLD_LOW
0
- + GAIN_MAX
in mV for single-ended inputs- GAIN_MAX
- + GAIN_MAX
in mV for differential inputsTHRESHOLD_HI
0
- + GAIN_MAX
in mV for single-ended inputs- GAIN_MAX
- + GAIN_MAX
in mV for differential inputsCOMP_MODE
Comparator mode
ads1115.CMODE_TRAD
traditional comparator mode (with hysteresis)ads1115.CMODE_WINDOW
window comparator modenote: Comparator and conversion ready are always configured to non-latching, active low.
nil
local id, sda, scl = 0, 6, 5
i2c.setup(id, sda, scl, i2c.SLOW)
ads1115.reset()
adc1 = ads1115.ads1015(id, ads1115.ADDR_GND)
adc1:setting(ads1115.GAIN_6_144V, ads1115.DR_3300SPS, ads1115.SINGLE_0, ads1115.SINGLE_SHOT)
Starts the ADC reading for single-shot mode and after the conversion is done it will invoke an optional callback function in which the ADC conversion result can be obtained.
device:startread([CALLBACK])
CALLBACK
callback function which will be invoked after the adc conversion is done
function(volt, volt_dec, adc, sign) end
nil
local id, alert_pin, sda, scl = 0, 7, 6, 5
i2c.setup(id, sda, scl, i2c.SLOW)
ads1115.reset()
adc1 = ads1115.ads1115(id, ads1115.ADDR_VDD)
-- single shot
adc1:setting(ads1115.GAIN_6_144V, ads1115.DR_128SPS, ads1115.SINGLE_0, ads1115.SINGLE_SHOT)
-- start adc conversion and get result in callback after conversion is ready
adc1:startread(function(volt, volt_dec, adc, sign) print(volt, volt_dec, adc, sign) end)
-- conversion ready
adc1:setting(ads1115.GAIN_6_144V, ads1115.DR_128SPS, ads1115.SINGLE_0, ads1115.SINGLE_SHOT, ads1115.CONV_RDY_1)
local function conversion_ready(level, when)
gpio.trig(alert_pin)
volt, volt_dec, adc, sign = adc1:read()
print(volt, volt_dec, adc, sign)
end
gpio.mode(alert_pin, gpio.INT)
gpio.trig(alert_pin, "down", conversion_ready)
-- start conversion and get result with read() after conversion ready pin asserts
adc1:startread()