I2C problem between the NXT and a Maxim DAC

[Kosen]

Hi everyone.

I'm using LabView 2009 service pack 1 an a NXT firmware 1.28 .

My goal is to command an DAC "MAX 127" from Maxim through a NXT. The DAC is connected to the NXT by the sensor plug.

Here the doc :

MAX 127 documentation

I got some problems. I can not discuss with the DAC, with the NXT module "i2c communication".

I don't see any digital signal on the oscilloscope.

Could you help me to fix it.

Sincerly

Remi Cambuzat

[Eric.M]

Hey Remi,

According to the Max127 DAC, to make sure the device is I²C compatible, you have to wire the SDA and SCL inputs to pull-up resistors. Did you do that ?

You should find some useful examples shipped with the NXT module (in LV : Help -> Find Examples -> Toolkits & Modules -> NXT).

As a last resort, you may need to upgrade to LV2010 because we have been experiencing some issue with I²C between LV 2009 and NXT 1.28.

Regards

[Kosen]

Thanks for the answer.

I got some pull-up resistor on SDA & SCL.

Here is the scheme :

I've instaled the NXT modules on Labview 2009 and it seems possible to use the I2C protocoles.

Do you think the easiest way is to upgrade to LV 2010 ?

Sincerly