RFM12 FS20

RFM12 FS20
Status	In Development
menuconfig	I/O->RFM12 ASK->868MHz
Pinning	yes
Ecmd	yes
Control6	no
Depends on	ECMD RFM12 ASK
Requires	-
Code	https://github.com/ethersex/ethersex/tree/master/hardware/radio/rfm12

The FS20 / FHT system by ELV is currently the most successful wireless home control system in the low cost sector. This arises from the large number of components and the continuous expansion of the system. But the relatively low price, the comprehensive home control systems far below the price of such EIB systems permits, plays a crucial role.

This FS20 modul is based on CULFW by Rudolf Koenig and supports a wide range of protocols:

• FS20: send/receive
  There are numerous FS20 devices, all of them are fully supported.
• FHT: send/receive
  Communication to the FHT80b is supported.
• S300: receive
  Examples of such devices: S300TH, KS300-2
• EM1000: receive
  Devices: EM1000FM, EM1000GZ, EM1000WZ
• HMS: receive
  Devices: There are numerous HMS devices, all of them are fully supported.
• ESA2000: receive
• Lacrosse TX2/TX3: receive

Connection

The RFM12 is connected to the ATmega like in FSK Mode with a small difference. The output FSK/DATA/nFSS signal (Pin 3) is connected to one of the INT pins of the ATmega.

The software uses the digital filter of the RFM12. To improve sensitivity on short and long distances the C_arssi capacitor needs to be replaced with a value 150 pf.

The SPI connection is pretty fixed and does not need special pinnings. For the chip select (CS) of the modul and the optional LEDs the pinning must be defined.

 /* port the rfm12 module CS is attached to */
 pin(SPI_CS_RFM12_0, PB0, OUTPUT)
  
 /* port the LEDS for rfm12 tx/rx attached to */
 pin(STATUSLED_RFM12_TX, PB3, OUTPUT)
 pin(STATUSLED_RFM12_RX, PB1, OUTPUT)
  
 RFM12_FS20_USE_INT(1)

If more than one RFM12 are used with Ethersex, the number in SPI_CS_RFM12_0 defines the number of the module. Each needs its own pinning. The RFM12_FS20_USE_INT defines whether FSK/DATA/nFSS is connected to INT0, INT1 or INT2 of the ATmega.

Configuration

The FS20 system sends on 868,35 MHz, so the 868MHz option is the right one.

 | |     I/O  --->                                               | |
 ...
 | |       [*] RFM12 ASK  --->                                   | |
 ...
 | |         [ ] 433MHz                                          | |
 | |         [-] Pollin/Kangtai Powerswitch (IC 2272)            | |
 | |         [-] Pollin Powerswitch buried (IC 1527)             | |
 | |         [-] Tevion Powerswitch                              | |
 | |         [-] Intertechno ITS-150                             | |
 | |         [-] External filter                                 | |
 | |         [-] Sensing                                         | |
 | |         ---                                                 | |
 | |         [*] 868MHz                                          | |
 | |         (0)   RFM12 select                                  | |
 | |         [*] FS20                                            | |
 | |         [*] FHT                                             | |
 | |         [*] ESA                                             | |
 | |         --- Debugging Flags                                 | |
 | |         [-] Sensing                                         | |
 | |         [ ] FS20                                            | |

ECMD

RFM12 FS20 implements an ECMD interface for send FS20/FHT commands. See ECMD reference.