[FAQ] TPS650332-Q1: How to make CRC for TPS650332-Q1 I2C communication?

Phil Yi40

Part Number: TPS650332-Q1

All production devices with function safety like TPS650332xx-Q1 have the I2C_CRC enabled. Please read through the description below:

The TPS650332-Q1 device uses this polynomial to calculate the checksum value on every bit except the ACK and NACK bits it receives from the MCU during a write protocol. The device compares this calculated checksum with the MCRC checksum value which the device receives from the MCU. The device also uses this polynomialto calculate the SCRC checksum value based on every bit except the ACK and NACK bits which the device transmits to the MCU during a read protocol. The master device (MCU) must use this same polynomial to calculate the checksum value based on the bits which the MCU receives from the device. The MCU must
compare this calculated checksum with the SCRC checksum value which it receives from the device.

Please be noted the device address is actually included twice, once for the device ID and once for the read command.

For example; the CRC byte 0x7D is sent by the PMIC for register 0x36 with data 0x16; please see the calculation below using the calculator in link below:

http://www.sunshine2k.de/coding/javascript/crc/crc_js.html