INA226

Franco Degioanni

Other Parts Discussed in Thread: INA226

Hello, i`m using the INA226 and i have problems with the slave direction.

When i use: A0 A1 = 00,01,10,11 i dint't have problems, but when i try to use A0 A1 = SCL,SDA, SCL X, SDA X.... i can not recognize the address.

Thank you

over 12 years ago

0 Jason Bridgmon over 12 years ago

TI__Genius 14825 points

Franco,

Are you using the EVM board or a board of your own design? Can you share the schematic of your board if possible (or email it to me at [email removed])? I would be happy to help you with debugging your solution.

Thanks!

Jason Bridgmon

0 Dmitry Tarasov over 11 years ago in reply to Jason Bridgmon

Prodigy 70 points

Hi, Jason!
I have a similar problem. But I can not communicate with INA226 with A0-A1 combination GND-GND.
I don't understand reasons of such behaviour. IC is the only slave on PCB. Host is Atmel MCU. Pull-ups on SDA and SCL lines are 12 kOhms. Logic analyzer shows normal data sequences from MCU. I tested all adresses from 0x00 to 0xfe but didn't get acknowledge of INA226.
May be the reason of that abscence of any connections to shunt resistor?

Sencirely yours,
Dmitry

0 Rabab Itarsiwala over 11 years ago in reply to Dmitry Tarasov

TI__Expert 4595 points

Dmitry,
INA226 should acknowledge to the corresponding address even in the absence of a shunt resistor. Are other A0-A1 combinations working for you?

0 Dmitry Tarasov over 11 years ago in reply to Rabab Itarsiwala

Prodigy 70 points

Well... It's quite obviously that IC should work in absence of shunt, but it was the only difference with the default scheme.

I didn't try any other combinations cause I didn't expect problems here and had made a PCB with no possibility of change address.

Thank you for idea, i'll try it. =)

0 Rabab Itarsiwala over 11 years ago in reply to Dmitry Tarasov

TI__Expert 4595 points

Dmitry,

Also check that the Address pins, INA226 and the I2C Master are all connected to the same GND.

0 Dmitry Tarasov over 11 years ago in reply to Rabab Itarsiwala

Prodigy 70 points

Checked =) I rather familiar with this error.

May be ATMega16's TWI is not just so easy compatible with I2C interface?

0 Jason Bridgmon over 11 years ago in reply to Dmitry Tarasov

TI__Genius 14825 points

Dmitry,

Were you able to communicate with the INA226 using a different address, possibly by cutting a trace or lifting a pin?

Would you share your schematic and possibly screenshots from an oscilloscope showing the failed I2C transactions?

Can you see SCL and SDA moving when you probe at the pins of the ATMega16 and at the pins of the INA226?

I'm not very familiar with the ATMega16 TWI but if it is I2C compatible and follows the timing specs for the INA226 at the speed you are using it, then it should be ok. How fast are you trying to run SCL?

Have you tried a smaller pull-up, like 4.7k? (If you do use a smaller pull-up, make sure you don't violate any of the input-current to any pin specs with too much pull-up voltage.)

What power supply voltages are you using for the ATMega16 chip, the INA226, and the pullups? Are they all the same?

0 Dmitry Tarasov over 11 years ago in reply to Jason Bridgmon

Prodigy 70 points

Hello again!
I'm sorry for some panic. The problem was solved.
The reason was high capasitance of SDA and SCL lines. First i thought that capasitance is ok cause exactly that line worked fine with another IC with I2C-interface (I worked with INA226 via debug platform). IC communication became fine as I set MCU on my gadget.

Sencirely yours,
Dmitry

p.s.: thanks for great production =)

0 Rabab Itarsiwala over 11 years ago in reply to Dmitry Tarasov

TI__Expert 4595 points

Hello Dmitry,
Glad that the problem was solved. Please let us know if you have any questions regarding TI parts in the future.

0 Dmitry Tarasov over 11 years ago in reply to Rabab Itarsiwala

Prodigy 70 points

Thank you. It's pleasant to work with you. =)

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