We are designing a stand-alone device that our customers can use to track the health of their batteries. We are trying to interface with a battery that uses a bq27541 as its fuel gauge. We have had difficulties in getting any data off the fuel gauge. Using I2C, we are able to get an ACK back from the battery when we write out the address 0xAA. When we then write out, for example, 0x08 (first byte of Voltage() cmd) we get a NACK. Any data we send after the address gets NACKed. I have tried multiple clock frequencies (100kHZ, 400Khz, <100kHZ) without any change. I know the I2C is working because I can and have read data from other devices. Is there something I need to do to gain access to these registers. I only need to be able to read the registers which shouldn't be protected even if the battery is SEALED. Any help on this would be appreciated.
Thanks
Chris J.