SBAS856D June 2017 – May 2019 DAC8740H , DAC8741H
PRODUCTION DATA.
The SPI interface includes an optional CRC mode to enhance the reliability of the interface by blocking erroneous commands sent to the device due to noise or other errors sources. When writing to or reading from the device the last 8-bits in the frame contain the CRC word which is calculated based on the polynomial x8 + x2 + x + 1. If a bad CRC word is included in a write-frame to the device, the frame will be ignored. When reading from the device, the host controller should check the CRC word to validate the frame.
Read commands with a bad CRC value will output 0x80000000 and, in the case of a receive FIFO read, prevent data from leaving the FIFO and subsequently being lost.