SE050E I2C Master problems with Raspberry Pi

[bh20]

I am trying to use a Rasberry Pi to talk to a sensor through the EdgeLock SE050E (OM-SE050ARD-E). I followed the NXP guide to setting up the RPi and installed the SE-PLUG-TRUST-MW_04.07.01.zip for the SE050E. I can run binaries like se05_GetInfo and se05_Minimal without a problem. 

I used code in se05x_I2cMaster.c as a template to talk to a sensor, but am unsuccessful at just reading a single register. When i check the status of TLV[].cmd.w.wrStatus and TLV[].cmd.rd.rdStatus after the write and read commands they both show 0x01, which apparently means NACK Failed, and no register data is received.

Any help would be appreciated.

[bh20]

@Fabian_R The jumps in you document helped. I was originally using AN12395 Sec 5.3 as a reference. 

@msjcard I was able to get a logical analyzer and can read the i2c bus from the SE to the sensor but the output doesn't make sense (see attachment) The i2c message are not correct the Writes and Reads are not as expected. I can trace the the bus from the RPi to the SE and the trace is as expected (not wierd). My sensor is a DS3231 real-time clk (addr = 0x68) and I can read the seconds register (0x00) directly from the RPi without any problems. 

I am using code directly adapted from demo/se0x_i2c_Master.c. My TLV[].cmd.w.wrStatus is still NACK Fail (0x01), however  TLV[].cmd.rd.rdStatus is Success (0x5A, i guess it is reading the error well). Maybe I dont understand the TVL[] order when it gets passed to Se05x_i2c_master_txn() although it seems strait forward. 

Thanks for the help.

[msjcard]

Do you have a more detailed logic analyzer setup? E.g. down to the bit and wave form level? Seeing exactly what's on the SDA line would be useful.

This almost looks like a baud rate mismatch issue. The DS3231 mentions a rate of 400khz, but you appear to be using a 100KHz rate to talk to it. Maybe try 400KHz?

The other random possibility you might want to check is if you have SDA and SCL reversed (e.g. IO1 and IO2).

[Fabian_R]

Hello, I've been assigned to support your case.
Thank you for your interest in our products.
Could you please clarify if your connection diagram is similar to section 5.17.1 from AN13030?
It is very important to short Jumper J9 and J10 as well.
What sensor are you trying to use?
It is also very important to share your logic analyzer findings for I2C.
Please keep in mind that the more information you provide, the better our support can be.

[msjcard]

Have you tried looking at the I2C bus directly to see what's being sent/received?

I've had good luck with the Saleae Logic 8 logic analyzer.  My wild guess is that it's a hardware issue of some sort - maybe a short in one of the pull down resistors. 

Other thing to try is to plug the sensor onto an I2C bus direct to the raspberry pi and see if it responds.