C:\Users\ADMINI~1\AppData\Local\Temp\cc9zl9qr.ltrans0.ltrans.o: In function `oled_flush':
C:\Users\ADMINI~1\AppData\Local\Temp\arduino_build_31448\sketch/oled.c:108: undefined reference to `spi_transfer_nr'
C:\Users\ADMINI~1\AppData\Local\Temp\arduino_build_31448\sketch/oled.c:109: undefined reference to `spi_transfer_nr'
C:\Users\ADMINI~1\AppData\Local\Temp\arduino_build_31448\sketch/oled.c:110: undefined reference to `spi_transfer_nr'
C:\Users\ADMINI~1\AppData\Local\Temp\arduino_build_31448\sketch/oled.c:112: undefined reference to `spi_transfer_nr'
C:\Users\ADMINI~1\AppData\Local\Temp\arduino_build_31448\sketch/oled.c:113: undefined reference to `spi_transfer_nr'
C:\Users\ADMINI~1\AppData\Local\Temp\cc9zl9qr.ltrans0.ltrans.o:C:\Users\ADMINI~1\AppData\Local\Temp\arduino_build_31448\sketch/oled.c:114: more undefined references to `spi_transfer_nr' follow
C:\Users\ADMINI~1\AppData\Local\Temp\cc9zl9qr.ltrans0.ltrans.o: In function `oled_flush':
C:\Users\ADMINI~1\AppData\Local\Temp\arduino_build_31448\sketch/oled.c:108: undefined reference to `spi_transfer_nr'
C:\Users\ADMINI~1\AppData\Local\Temp\arduino_build_31448\sketch/oled.c:109: undefined reference to `spi_transfer_nr'
C:\Users\ADMINI~1\AppData\Local\Temp\arduino_build_31448\sketch/oled.c:110: undefined reference to `spi_transfer_nr'
C:\Users\ADMINI~1\AppData\Local\Temp\arduino_build_31448\sketch/oled.c:112: undefined reference to `spi_transfer_nr'
C:\Users\ADMINI~1\AppData\Local\Temp\arduino_build_31448\sketch/oled.c:113: undefined reference to `spi_transfer_nr'
C:\Users\ADMINI~1\AppData\Local\Temp\cc9zl9qr.ltrans0.ltrans.o:C:\Users\ADMINI~1\AppData\Local\Temp\arduino_build_31448\sketch/oled.c:114: more undefined references to `spi_transfer_nr' follow
collect2.exe: error: ld returned 1 exit status
exit status 1 为开发板 Arduino Leonardo 编译时出错。