Zoltan Hudak / RawEthernet

Enables fast realtime communication over Ethernet by using plain Ethernet frames (overhead of TCP/IP network layers is stripped away).

Dependents:   RawEthernet_Hello

RawEthernet.h@0:ca476e0a1a28, 2018-08-20 (annotated)

Committer:
hudakz
Date:
Mon Aug 20 11:37:35 2018 +0000
Revision:
0:ca476e0a1a28
Initial release.

Who changed what in which revision?

UserRevisionLine numberNew contents of line
hudakz 0:ca476e0a1a28 1 #ifndef RAW_ETHERNET_H
hudakz 0:ca476e0a1a28 2 #define RAW_ETHERNET_H
hudakz 0:ca476e0a1a28 3
hudakz 0:ca476e0a1a28 4 #include "mbed.h"
hudakz 0:ca476e0a1a28 5
hudakz 0:ca476e0a1a28 6 //------------------------------------------------------------------------------
hudakz 0:ca476e0a1a28 7 // Functions for using an ENC28J60 ethernet controller, optimized for
hudakz 0:ca476e0a1a28 8 // communication speed.
hudakz 0:ca476e0a1a28 9 //
hudakz 0:ca476e0a1a28 10 // Written by Rogier Schouten for AVR micro controllers http://www.rogiershikes.tk
hudakz 0:ca476e0a1a28 11 // Based on code by Guido Socher http://www.tuxgraphics.org
hudakz 0:ca476e0a1a28 12 // Idea modified and further updated by Guido Socher
hudakz 0:ca476e0a1a28 13 // Ported to MBED by Zoltan Hudak hudakz@outlook.com
hudakz 0:ca476e0a1a28 14 // License: GPL V2
hudakz 0:ca476e0a1a28 15 //
hudakz 0:ca476e0a1a28 16 // Enables to read sensor data or control IO-ports with less than a millisecond delay.
hudakz 0:ca476e0a1a28 17 // The trick is in removing the TCP/IP overhead and use raw Ethernet frames.
hudakz 0:ca476e0a1a28 18 // A Linux application using raw network sockets is controlling this slave device.
hudakz 0:ca476e0a1a28 19 //
hudakz 0:ca476e0a1a28 20 // Assumptions:
hudakz 0:ca476e0a1a28 21 // - Max. payload data: 255 bytes per packet
hudakz 0:ca476e0a1a28 22 // - The network consists of a master PC and one or more slave devices.
hudakz 0:ca476e0a1a28 23 // Only plain hubs and switches are allowed between PC and ethernet device.
hudakz 0:ca476e0a1a28 24 // Note that some wlan routers have internal switches which switch only
hudakz 0:ca476e0a1a28 25 // IP packets. They will discard plain ethernet frames. A normal 100Mbit
hudakz 0:ca476e0a1a28 26 // office/workgroup switch will however work.
hudakz 0:ca476e0a1a28 27 //
hudakz 0:ca476e0a1a28 28 // Based on these assumptions, we can optimize the protocol for faster communication:
hudakz 0:ca476e0a1a28 29 // - Master and slave send unicast packets.
hudakz 0:ca476e0a1a28 30 // - We use raw ethernet and no higher-level protocol such as UDP or TCP/IP
hudakz 0:ca476e0a1a28 31 // - We use the EtherType field of a packet as a length field. Actually, we only
hudakz 0:ca476e0a1a28 32 // use one byte of it since we have max 255 length packets.
hudakz 0:ca476e0a1a28 33 //
hudakz 0:ca476e0a1a28 34 // Furthermore, there are a few code optimizations:
hudakz 0:ca476e0a1a28 35 // - Minimize communication between ENC and MCU.
hudakz 0:ca476e0a1a28 36 // - No unnecessary memory bank checks
hudakz 0:ca476e0a1a28 37 //
hudakz 0:ca476e0a1a28 38
hudakz 0:ca476e0a1a28 39 class RawEthernet
hudakz 0:ca476e0a1a28 40 {
hudakz 0:ca476e0a1a28 41 public:
hudakz 0:ca476e0a1a28 42 /**
hudakz 0:ca476e0a1a28 43 * Constructor
hudakz 0:ca476e0a1a28 44 *
hudakz 0:ca476e0a1a28 45 * \param mosi mbed pin to use SPI
hudakz 0:ca476e0a1a28 46 * \param miso mbed pin to use SPI
hudakz 0:ca476e0a1a28 47 * \param sclk mbed pin to use SPI
hudakz 0:ca476e0a1a28 48 * \param cs pin to select the ENC28J60 chip
hudakz 0:ca476e0a1a28 49 */
hudakz 0:ca476e0a1a28 50 RawEthernet(PinName mosi, PinName miso, PinName sclk, PinName cs, uint8_t myMac[6], uint8_t myIp[4]);
hudakz 0:ca476e0a1a28 51 void linkTo(uint8_t remoteMac[6]);
hudakz 0:ca476e0a1a28 52 void packetSend(uint16_t len, uint8_t* packet);
hudakz 0:ca476e0a1a28 53 bool isLinkUp(void);
hudakz 0:ca476e0a1a28 54 uint8_t receive(uint8_t* buf, uint8_t maxlen);
hudakz 0:ca476e0a1a28 55 void gratuitousArp();
hudakz 0:ca476e0a1a28 56 void send(uint8_t* buf, uint8_t len);
hudakz 0:ca476e0a1a28 57 uint8_t getRev(void);
hudakz 0:ca476e0a1a28 58 protected:
hudakz 0:ca476e0a1a28 59 uint8_t readOp(uint8_t op, uint8_t address);
hudakz 0:ca476e0a1a28 60 void writeOp(uint8_t op, uint8_t address, uint8_t data);
hudakz 0:ca476e0a1a28 61 uint8_t readReg(uint8_t address);
hudakz 0:ca476e0a1a28 62 void writeReg(uint8_t address, uint8_t data);
hudakz 0:ca476e0a1a28 63 void setBank(uint8_t address);
hudakz 0:ca476e0a1a28 64 void readBuffer(uint16_t len, uint8_t* data);
hudakz 0:ca476e0a1a28 65 void writeBuffer(uint16_t len, uint8_t* data);
hudakz 0:ca476e0a1a28 66 uint16_t phyReadH(uint8_t address);
hudakz 0:ca476e0a1a28 67 void phyWrite(uint8_t address, uint16_t data);
hudakz 0:ca476e0a1a28 68 private:
hudakz 0:ca476e0a1a28 69 SPI _spi;
hudakz 0:ca476e0a1a28 70 DigitalOut _cs;
hudakz 0:ca476e0a1a28 71 uint8_t _bank;
hudakz 0:ca476e0a1a28 72 int16_t _nextPacketPtr;
hudakz 0:ca476e0a1a28 73 uint8_t _lastTransmitPayloadLen;
hudakz 0:ca476e0a1a28 74 uint8_t _mac[6];
hudakz 0:ca476e0a1a28 75 uint8_t _ip[4];
hudakz 0:ca476e0a1a28 76 uint8_t _remoteMac[6];
hudakz 0:ca476e0a1a28 77 static char _arpReqHdr[10];
hudakz 0:ca476e0a1a28 78 };
hudakz 0:ca476e0a1a28 79 #endif // RAW_ETHERNET_H