Unable to establish I2C communication

When the batteries are properly connected, then communication or a charge source connection at PCKP will wake the device up.  The REG2/REG3 pins are a good sign of life from the IC.  When the IC is powered up, this will have 1.8V/3.4V respectively.

What battery voltage is measured at the BATT pin?  

If the REG2/3 pins show the device is active, can you can all I2C addresses to confirm if any are responding?

Have you tested your communication on the EVKIT hardware?

Thanks

Jason

When the batteries are properly connected, then communication or a charge source connection at PCKP will wake the device up.  The REG2/REG3 pins are a good sign of life from the IC.  When the IC is powered up, this will have 1.8V/3.4V respectively.

What battery voltage is measured at the BATT pin?  

If the REG2/3 pins show the device is active, can you can all I2C addresses to confirm if any are responding?

Have you tested your communication on the EVKIT hardware?

Thanks

Jason

We are using 3.7V x 4 Li-Po batteries and measuring 14.8V across BATTP and BATTN.

Also we are able to measure 1.8V across REG2 and 3.4V across REG3 respectively.

We don't have the EVK on hand, so we did  not test it on EVK but the schematic is designed referring the EVK schematic. 

What is the current rating of the regulators REG2 and REG3? We did not get this information in the DATASHEET. 

The pins are for internal use only and should not be loaded externally, so we do not have a current rating for those pins.

It sounds like the MAX17320 is properly powered.  Can you measure the voltage at the CHG and DIS pins and the respective gates of the FETs?  Is the voltage at the CHG/DIS pin properly reaching the gate pin of the FET?

Are you able to get any scope shots of the communication so we can see if that looks ok?

CHG Pin measures 16V and DIS Pin measures 2.4V both at IC Pins and FET Gate pins.

We are able to establish communication only after connecting host controller ground to CSP but as per the EVK schematic host controllers ground should be connected to CSN (SYSN) 

Isn't this violation to the EVK schematic? because now the host controller is directly connected to the battery ground(BATT-) and not to the PACK- as shown in the EVK schematic.

The Sense resistor should be the only difference between the BATT- and SYS- terminals.  Communication can typially occur with gnd at either terminal, but for proper current measurement, the proper connection on either side of the sense resistor is required.  I would recommend verifying the sense resistor is connected correctly and perhaps reflow the connection of the sense resistor.

When you are able to communicate, are you able to read all of the registers correctly?

The BATT and PCKP register values when calculated are correct, but individual cell voltage and average voltages seems to be wrong.

Regarding the ground,

We have tested on 3 PCB's, all showing same behaviour and both grounds are showing continuity when checked.

If the cell voltages are incorrect, then the device may be opening the DIS fet to protect from UVP.

What are the cell voltages reading?

Does the ProtStatus register indicate there are any protection faults?

This is what we read from the IC. The displayed values are not byte-swapped, while checking 16bit data, byte-swapping is needed.

We tried to set the DISs bit of HProtCfg2 register to turn on the DIS FET, but write operation didn't reflect when read back.

Isn't the DIS FET should be ON by default?

ProtStatus shows the TooColdC bit and the UVP bits are set.  If UVP is set, then discharging is disabled and DIS pin will be low.

Your Cell voltages are showing only Cell 2 is being read correctly 0xB871 = 3.688V, but all the other cells are reading 0.  If any cell voltage is below the UVP threshold, then the UVP bit will be set and the DIS fet will be opened to prevent any additional discharge.  I'd start by verifying your cell voltage connections and getting those readings to be reflected properly by the IC.