nau7802

NAU7802 A/D converter library for Node.js

It supports I2C.1 and I2C.2 of Raspberry Pi.

Installation

npm install nau7802

Enable I2C

If it's the first time to use the I2C functionalities of your Raspberry Pi, some steps are needed to enable them.

Run

sudo raspi-config

on the terminal. It will open the software and hardware config tool. Select "5 Interfacing Options" > "P5 I2C", then select "YES" to the question "Would you like the ARM I2C interface to be enabled?". After closing the tool by < Finish > button, you are ready to use I2C!

Example

const NAU7802 = require('nau7802');

const adc = new NAU7802(1); // NAU7802 is connected to I2C.1 bus
adc.start();
adc.selectChannel1(); // Select channel
adc.setRate80SPS(); // Sampling rate
adc.startCycle();

setInterval(()=>{
  console.log("ADC value=%d", adc.readADCValue());
  }, 1000);

API

constructor (i2cBusNumber)

• i2cBusNumber : Number of I2C bus (1 or 2). If not specified, I2C.1 will be selected.

start ()

Open I2C, reset all registers and start analog to digital conversion.

resetResisters ()

Reset all registers of NAU7802.

calibrate ()

Start calibration and wait until it finishes.

setRate10SPS ()

Select conversion rate.

setRate20SPS ()

Select conversion rate.

setRate40SPS ()

Select conversion rate.

setRate80SPS ()

Select conversion rate.

setRate320SPS ()

Select conversion rate. 320SPS is the default value.

selectChannel1 ()

Select Channel 1 and calibrate.

selectChannel2 ()

Select Channel 1 and calibrate.

startCycle ()

Start conversion cycle manually.

readADCValue ()

Read 24-bit value of A/D conversion result. It returns signed value.

getRevision ()

Read the revision code.

setRegValue (regAddress, value)

Set a register's value.

• regAddress : Register address
• value : Byte to write

readRegValue (regAddress)

Read a register's current value.

• regAddress : Register address

setRegisterBit (regAddress, bitIndex)

Set a register's single bit to 1.

• regAddress : Register address
• index : Bit index

setRegisterBit (regAddress, bitIndex)

Clear a register's single bit to 0.

• regAddress : Register address
• index : Bit index

waitForBitValue (regAddress, bitIndex, bitValue, timeoutMsec)

Wait until the specified bit value become true or false.

• regAddress : Register address
• bitIndex : Bit bit index
• bitValue : Desired value (0 or 1)
• timeoutMsec : Timeout (msec)