Implementation of f-MAC algorithm, based on “f-MAC: A Deterministic Media Access Control Protocol Without Time Synchronization” by Utz Roedig, Andre Barroso and Cormac J. Sreenan for Infineon’s TDA5340 TRX and XMC4500/XMC1100 microcontroller.
Install ARM’s GCC for Linux and clone dependencies (see below). The release 2017q1 is known to work. Edit the Makefile (BOARD=) depending on your target, then run make, which creates a binary in bin/.
While OpenOCD should work in theory, Segger’s JLink tools are usually faster (albeit less stable). For the XMC4500 Relax Kit run:
JLinkGDBServer -select USB=$(USBID) -x foo.jlink -device XMC4500-1024 -if swd -port 3333 -localhostonly 1
The XMC1100 (csmTDA) you can use -device XMC1100-32 instead. Then make
gdb starts the GNU debugger. Then load, monitor reset and
continue to flash and run the program.
Unless several DEBUG_* options in config.h are set, this code will do
nothing, unless configured via SPI/UART.
- READBUF
- Master sends command 01h. Slave responds with one packet from the FIFO.
- WRITEBUF
- Master sends command 02h, followed by packet data. No response.
- READREG
- Master sends command 03h and a 8 bit register number (see below). Slave responds with 32 bit register value.
- WRITEREG
- Master sends command 04h, a 8 bit register number and a 32 bit register value. No response.
Available registers:
- RXPENDING: 02h
- Number of received packets in FIFO (max 2, see function initFifos)
- TXPENDING: 03h
- Number of packets waiting to be transmitted (max 2)
- CONFIG: 05h
- From LSB to MSB, each one byte: Station ID, number of stations, payload size (max 32 bytes)
SPI uses the configuration parameters CLK_PH=1 and CLK_POL=0. For the correct
pinout see the top of spiclient.c. Since response times cannot be guaranteed,
the SPI protocol uses to steps. First, hold SS low, then send a request and
pull SS high again. After pulling SS low again the code will respond with
undefined words until a sync word AAh is received. The actual response
follows. Write requests have no response.
UART uses 9600 baud, 8 data bits, 1 stop bit (see spiclientInit) and the same MOSI/MISO pins for communication. At the end of every message (request or response) a break symbol (hold down data line for more cycles than wordlength) must be sent to terminate the message.
These files are important, everything else is just boilerplate.
- fmac.c
- The actual MAC implementation
- config.h
- A few compile-time configuration options
- spiclient.c
- SPI and UART slave implementation (disregard the name)
Dependencies are added to src/ as git submodules. These include:
- bitbite
- Bitstream helper functions
- dottedline
- 8b10b encoding
- prettylewis
- Hardware abstraction (HAL) for the TDA5340
- rtt
- SEGGER’s RTT library
- xmclib
- Infineon’s XMClib