Guidelines to Implement CRC Algorithm for the MAX22190 and MAX22192 Octal Industrial Digital Input with Diagnostics

Abstract: The MAX22190 and MAX22192 octal digital input devices are highly integrated, fault tolerant, current-sinking, IEC 61131-2 compliant industrial inputs. They translate the 24V inputs to a serialized SPI-compatible output. The SPI interface provides access to digital input data, diagnostic data, and advanced configuration. For added safety, a hardware CRC circuit optionally protects the SPI interface against bit errors. This application note provides example C-code implementing CRC generation and detection algorithms in the microcontroller.