A firmware driver for CC1100 based SubGHz RF modem. Target used is a PIC16F877A series. The code is written and tested for a RF modem by Summitek model ST-TR1100+PA. SPI is implemented in the software itself and can be driven in burst mode also. -A firmware driver for CC1100 based SubGHz RF modem. Target used is a PIC16F877A series. The code is written and tested for a RF modem by Summitek　model ST-TR1100+PA. SPI is implemented in the software itself and can be driven in burst mode also.