OPT3006: Latched/windowed mode and interrupts

We are using a 10k Ohm resister for int pull-up and 4.7k for I2C pull ups. I2C communications up to this point, have been flawless.  Once I receive the interrupt, I clear the interrupt on the chip(KL03) and wake up the main program.  There I read R1.  FL or FH is high, depending on the condition.

After that, I read R0.  The R0 read returns from I2C with a NAK.  

How many devices do you see this on? Are you able to replicate on the EVM?

We only have one I2C device, hence this is coming from the OPT3006. 

The documentation says that the interrupt pin will remain active until we either send the SMBus alert or read the configuration register (R1). Table 4, page 15.  We are using the default (low) for the interrupt pin state.

We do receive the interrupt, but the problem is clearing that pin.  Once we get the first interrupt, we cannot clear that pin without a power cycle.  That's contrary to what the manual says.

I have, as I mentioned, our application attempts to read R1 and receives an I2C NAK response, and the interrupt pin remains active.  I have also attempted to send the SMBus alert message, with the same results.

As far as the EVM goes, that's connected to a PC via a USB.  The supplied program (LabView?) seems to function as expected; we see the appropriate flags on the R1 display.  That is, however, after we attempt to read R1 as it never appears to generate an interrupt on its own.  Using the Continuous switch, the program appears to pull R1 status, display that, then read R0.

Again, we configure the device, we get the interrupt, we can just never make the thing go away as we continue to get a NAK response to our I2C packets.

Hi Robert,

The NACK is strange and sounds like issue is not related to INT pin but rather some I2C issue. If the I2C read results in NACK then the read will not occur and INT will not be cleared. Does this mean after first data ready that your I2C comm with device does not work anymore (not able to read or write any registers)?

Best,

Alex

Yes, since I cannot successfully communicate with the device, the INT pin remains high and I constantly receive interrupts. A power cycle of the board is necessary to clear the device and the offending pin.  A reset, BTW, does not clear up this situation.

Is there some way to trace the commands going to/from the sensor via the EVM/LabView program?  I would like to know the command trace so that I might be able to duplicate the conversation.

Hi Robert,

I don't know of any easy way within labview (labview if sending command through USB to a chip on the SM-USB-DIG, which is then sending the i2c commands) and would suggest using scope with i2c monitor to get commands off the I2C line as the way to do that.

Best,

Alex