The main component of this VHDL project is a RFM12B physical layer component. A physical layer is the lowest component in the ISO/OSI model.
In the normal context the physical layer defines the electrical attributes of a communication, e.g. modulation/ demodulation, coding/ decoding. In this case the electrical attributes are already defined by the RFM12B component. Communication with the RFM12B is done through a SPI interface.
This PHY component implements the receiving and transmitting of a single byte through the RFM12B. It can be used by a data-link layer to transmit full frames.
Another component available in this project implements just the SPI communication with the RFM12B.
- TI-HSU SPI-Master component
The following Image shows all available signals:
| Signal Name | Length | Direction | Description |
|---|---|---|---|
| idData | 8 | IN | The byte to transmit |
| icFrame | 1 | IN | signals start and end of frame |
| icWe | 1 | IN | transmit idData, only works if ocChannelFree = 1 |
| ocChannelFree | 1 | OUT | signals if a new Byte can be transmitted |
| odData | 8 | OUT | received byte |
| ocValid | 1 | OUT | the received byte is valid when 1 |
| idFrameLength | 8 | IN | the length of a frame, can be changed during reception, RFM12B resets its transmission detection after this number of bytes |
| icPowerMode | 2 | IN | sets the power mode of the RFM12B |
| odSDI | 1 | OUT | SPI MOSI signal to the RFM12B |
| idSDO | 1 | IN | SPI MISO signal from the RFM12B |
| oSCLK | 1 | OUT | SPI Clock to the RFM12B |
| ocSELn | 1 | OUT | chip select signal to the RFM12B |
| icINTn | 1 | IN | interrupt input from the RFM12B |
| ocResetN | 1 | OUT | reset signal to the RFM12B |
| iClk | 1 | IN | system clock signal |
| iClkEn | 1 | IN | clock enable signal, shuts down the RFM12BPHY complely |
| iReset | 1 | IN | active high, clock synchronous reset signal |
More documentation can be found by generating the doxygen documentation or by looking into the VHDL files.
- 00 Receiver active and check channel for a transmission window
- 01 Receiver active and do not check channel for a transmission window
- 10 full shutdown of RFM12B, if you want more power down use the iClkEn signal
- 11 reserved
You can contribute to this project in different ways:
- find bugs and provide bug reports through githubs issue system
- find bugs and provide solutions as pull requests through github
- you want to actively improve the project and get access to our gerrit instance
For the last two ways just send an email to mailto:dmeyer@hsu-hh.de.
The RFM12B-PHY project is licensed under GPLv2.