text: #ifndef H7_SPI_EXAMPLE_CRC_H
  #define H7_SPI_EXAMPLE_CRC_H
  
  #include <stdint.h>
  
  // functions to calculate crc in streaming mode
  // first call pre, then call upd for each byte/array and in the end call post
  uint32_t crc32pre();
  uint32_t crc32upd(const uint8_t* bytes, uint16_t length, uint32_t crc);
  uint32_t crc32post(uint32_t crc);
  
  uint32_t crc32(uint8_t* bytes, uint16_t length);
  
  #endif //H7_SPI_EXAMPLE_CRC_H
  