SLUSB20C November 2012 – November 2021
The BQ27520-G4 fuel gauge supports the standard I2C read, incremental read, quick read, one byte write, and incremental write functions. The 7-bit device address (ADDR) is the most significant 7 bits of the hex address and is fixed as 1010101. The first 8-bits of the I2C protocol is, therefore, 0xAA or 0xAB for write or read, respectively.
The “quick read” returns data at the address indicated by the address pointer. The address pointer, a register internal to the I2C communication engine, increments whenever data is acknowledged by the fuel gauge or the I2C master. “Quick writes” function in the same manner and are a convenient means of sending multiple bytes to consecutive command locations (such as two-byte commands that require two bytes of data).
The following command sequences are not supported:
Attempt to write a read-only address (NACK after data sent by master):
Attempt to read an address above 0x6B (NACK command):