INA219 Driver

Toit

#INA219 Driver

Thread channel in help

wildlife-nature-tech 03/19/2023 05:55 AM

hi

toit is really great! I'm having fun with it on multiple devices. It was no problem to get into it all.

But I have problem to create a new driver for the Ina219 i2c sensor. I use other i2c drivers as blueprints. I get an I2C_READ_FAILED when I try to read the chip id.

bitphlipphar 03/19/2023 05:58 AM

Hi @wildlife-nature-tech! Have you tried scanning the i2c bus to make sure you have the right address?

bitphlipphar 03/19/2023 05:59 AM

import gpio
import i2c

main:
  bus := i2c.Bus
    --sda=gpio.Pin 21
    --scl=gpio.Pin 22
  print bus.scan

bitphlipphar 03/19/2023 05:59 AM

(something along those lines)

wildlife-nature-tech 03/19/2023 05:59 AM

yes I'm using the correct address from the scan result.

bitphlipphar 03/19/2023 05:59 AM

Cool.

bitphlipphar 03/19/2023 06:00 AM

Are you comfortable sharing some of the code you wrote for reading the chip id?

wildlife-nature-tech 03/19/2023 06:02 AM

import binary
import serial



class Ina219:
  static I2C_ADDRESS ::= 0x64

  static REG_CHIPID_           ::= 0x02
  
  d := null

  registers_/serial.Registers

  constructor dev/serial.Device:
    d = dev
    registers_ = dev.registers



    r := registers_.read_u8 REG_CHIPID_
    print "r $r"

(edited)

bitphlipphar 03/19/2023 07:00 AM

Are you following a datasheet or some sample?

floitsch 03/19/2023 10:26 AM

I think it's this sensor: http://www.ti.com/document-viewer/INA219/datasheet#SBOS4031990

INA219 datasheet | TI.com

INA219 Zerø-Drift, Bidirectional Current/Power Monitor With I2C Interface (Rev. G)

floitsch 03/19/2023 10:26 AM

The I2C address looks right.

floitsch 03/19/2023 10:28 AM

However the ina219 has an unusual way of reading data: one has to write to a certain address first which latches the address. When reading one doesn't write the address anymore. (Section 8.5.6)(edited)

floitsch 03/19/2023 10:28 AM

Also, every register in the sensor is 16 bits wide.

floitsch 03/19/2023 10:35 AM

So you would use device.write #[register_address] to set the address and then device.read 2 to read the 16 bit register.(edited)

wildlife-nature-tech 03/19/2023 06:30 PM

It was a stupid mistake. I have looked into multiple samples, documentations, data sheets and other driver implementations. I learned a lot and my love for Toit is getting bigger.
The I2C_ADDRESS was wrong in my driver

I saw the correct in the i2c scan but typed in wrong in the drive.
Tanks for your help and kind contact. Hope to publish the INA219 and INA3221 pkg soon.

floitsch 03/19/2023 06:31 PM

Glad it worked out.

16 messages in total