enc28j60.cpp

// Microchip ENC28J60 Ethernet Interface Driver
// Author: Guido Socher
// Copyright: GPL V2
//
// Based on the enc28j60.c file from the AVRlib library by Pascal Stang.
// For AVRlib See http://www.procyonengineering.com/
// Used with explicit permission of Pascal Stang.
//
// 2010-05-20 <jc@wippler.nl>

#if ARDUINO >= 100
#include <Arduino.h> // Arduino 1.0
#else
#include <Wprogram.h> // Arduino 0022
#endif
#include "enc28j60.h"

uint16_t ENC28J60::bufferSize;
bool ENC28J60::broadcast_enabled = false;

// ENC28J60 Control Registers
// Control register definitions are a combination of address,
// bank number, and Ethernet/MAC/PHY indicator bits.
// - Register address        (bits 0-4)
// - Bank number        (bits 5-6)
// - MAC/PHY indicator        (bit 7)
#define ADDR_MASK        0x1F
#define BANK_MASK        0x60
#define SPRD_MASK        0x80
// All-bank registers
#define EIE              0x1B
#define EIR              0x1C
#define ESTAT            0x1D
#define ECON2            0x1E
#define ECON1            0x1F
// Bank 0 registers
#define ERDPT           (0x00|0x00)
#define EWRPT           (0x02|0x00)
#define ETXST           (0x04|0x00)
#define ETXND           (0x06|0x00)
#define ERXST           (0x08|0x00)
#define ERXND           (0x0A|0x00)
#define ERXRDPT         (0x0C|0x00)
// #define ERXWRPT         (0x0E|0x00)
#define EDMAST          (0x10|0x00)
#define EDMAND          (0x12|0x00)
// #define EDMADST         (0x14|0x00)
#define EDMACS          (0x16|0x00)
// Bank 1 registers
#define EHT0             (0x00|0x20)
#define EHT1             (0x01|0x20)
#define EHT2             (0x02|0x20)
#define EHT3             (0x03|0x20)
#define EHT4             (0x04|0x20)
#define EHT5             (0x05|0x20)
#define EHT6             (0x06|0x20)
#define EHT7             (0x07|0x20)
#define EPMM0            (0x08|0x20)
#define EPMM1            (0x09|0x20)
#define EPMM2            (0x0A|0x20)
#define EPMM3            (0x0B|0x20)
#define EPMM4            (0x0C|0x20)
#define EPMM5            (0x0D|0x20)
#define EPMM6            (0x0E|0x20)
#define EPMM7            (0x0F|0x20)
#define EPMCS           (0x10|0x20)
// #define EPMO            (0x14|0x20)
#define EWOLIE           (0x16|0x20)
#define EWOLIR           (0x17|0x20)
#define ERXFCON          (0x18|0x20)
#define EPKTCNT          (0x19|0x20)
// Bank 2 registers
#define MACON1           (0x00|0x40|0x80)
#define MACON2           (0x01|0x40|0x80)
#define MACON3           (0x02|0x40|0x80)
#define MACON4           (0x03|0x40|0x80)
#define MABBIPG          (0x04|0x40|0x80)
#define MAIPG           (0x06|0x40|0x80)
#define MACLCON1         (0x08|0x40|0x80)
#define MACLCON2         (0x09|0x40|0x80)
#define MAMXFL          (0x0A|0x40|0x80)
#define MAPHSUP          (0x0D|0x40|0x80)
#define MICON            (0x11|0x40|0x80)
#define MICMD            (0x12|0x40|0x80)
#define MIREGADR         (0x14|0x40|0x80)
#define MIWR            (0x16|0x40|0x80)
#define MIRD            (0x18|0x40|0x80)
// Bank 3 registers
#define MAADR1           (0x00|0x60|0x80)
#define MAADR0           (0x01|0x60|0x80)
#define MAADR3           (0x02|0x60|0x80)
#define MAADR2           (0x03|0x60|0x80)
#define MAADR5           (0x04|0x60|0x80)
#define MAADR4           (0x05|0x60|0x80)
#define EBSTSD           (0x06|0x60)
#define EBSTCON          (0x07|0x60)
#define EBSTCS          (0x08|0x60)
#define MISTAT           (0x0A|0x60|0x80)
#define EREVID           (0x12|0x60)
#define ECOCON           (0x15|0x60)
#define EFLOCON          (0x17|0x60)
#define EPAUS           (0x18|0x60)

// ENC28J60 ERXFCON Register Bit Definitions
#define ERXFCON_UCEN     0x80
#define ERXFCON_ANDOR    0x40
#define ERXFCON_CRCEN    0x20
#define ERXFCON_PMEN     0x10
#define ERXFCON_MPEN     0x08
#define ERXFCON_HTEN     0x04
#define ERXFCON_MCEN     0x02
#define ERXFCON_BCEN     0x01
// ENC28J60 EIE Register Bit Definitions
#define EIE_INTIE        0x80
#define EIE_PKTIE        0x40
#define EIE_DMAIE        0x20
#define EIE_LINKIE       0x10
#define EIE_TXIE         0x08
#define EIE_WOLIE        0x04
#define EIE_TXERIE       0x02
#define EIE_RXERIE       0x01
// ENC28J60 EIR Register Bit Definitions
#define EIR_PKTIF        0x40
#define EIR_DMAIF        0x20
#define EIR_LINKIF       0x10
#define EIR_TXIF         0x08
#define EIR_WOLIF        0x04
#define EIR_TXERIF       0x02
#define EIR_RXERIF       0x01
// ENC28J60 ESTAT Register Bit Definitions
#define ESTAT_INT        0x80
#define ESTAT_LATECOL    0x10
#define ESTAT_RXBUSY     0x04
#define ESTAT_TXABRT     0x02
#define ESTAT_CLKRDY     0x01
// ENC28J60 ECON2 Register Bit Definitions
#define ECON2_AUTOINC    0x80
#define ECON2_PKTDEC     0x40
#define ECON2_PWRSV      0x20
#define ECON2_VRPS       0x08
// ENC28J60 ECON1 Register Bit Definitions
#define ECON1_TXRST      0x80
#define ECON1_RXRST      0x40
#define ECON1_DMAST      0x20
#define ECON1_CSUMEN     0x10
#define ECON1_TXRTS      0x08
#define ECON1_RXEN       0x04
#define ECON1_BSEL1      0x02
#define ECON1_BSEL0      0x01
// ENC28J60 MACON1 Register Bit Definitions
#define MACON1_LOOPBK    0x10
#define MACON1_TXPAUS    0x08
#define MACON1_RXPAUS    0x04
#define MACON1_PASSALL   0x02
#define MACON1_MARXEN    0x01
// ENC28J60 MACON2 Register Bit Definitions
#define MACON2_MARST     0x80
#define MACON2_RNDRST    0x40
#define MACON2_MARXRST   0x08
#define MACON2_RFUNRST   0x04
#define MACON2_MATXRST   0x02
#define MACON2_TFUNRST   0x01
// ENC28J60 MACON3 Register Bit Definitions
#define MACON3_PADCFG2   0x80
#define MACON3_PADCFG1   0x40
#define MACON3_PADCFG0   0x20
#define MACON3_TXCRCEN   0x10
#define MACON3_PHDRLEN   0x08
#define MACON3_HFRMLEN   0x04
#define MACON3_FRMLNEN   0x02
#define MACON3_FULDPX    0x01
// ENC28J60 MICMD Register Bit Definitions
#define MICMD_MIISCAN    0x02
#define MICMD_MIIRD      0x01
// ENC28J60 MISTAT Register Bit Definitions
#define MISTAT_NVALID    0x04
#define MISTAT_SCAN      0x02
#define MISTAT_BUSY      0x01

// ENC28J60 EBSTCON Register Bit Definitions
#define EBSTCON_PSV2     0x80
#define EBSTCON_PSV1     0x40
#define EBSTCON_PSV0     0x20
#define EBSTCON_PSEL     0x10
#define EBSTCON_TMSEL1   0x08
#define EBSTCON_TMSEL0   0x04
#define EBSTCON_TME      0x02
#define EBSTCON_BISTST    0x01

// PHY registers
#define PHCON1           0x00
#define PHSTAT1          0x01
#define PHHID1           0x02
#define PHHID2           0x03
#define PHCON2           0x10
#define PHSTAT2          0x11
#define PHIE             0x12
#define PHIR             0x13
#define PHLCON           0x14

// ENC28J60 PHY PHCON1 Register Bit Definitions
#define PHCON1_PRST      0x8000
#define PHCON1_PLOOPBK   0x4000
#define PHCON1_PPWRSV    0x0800
#define PHCON1_PDPXMD    0x0100
// ENC28J60 PHY PHSTAT1 Register Bit Definitions
#define PHSTAT1_PFDPX    0x1000
#define PHSTAT1_PHDPX    0x0800
#define PHSTAT1_LLSTAT   0x0004
#define PHSTAT1_JBSTAT   0x0002
// ENC28J60 PHY PHCON2 Register Bit Definitions
#define PHCON2_FRCLINK   0x4000
#define PHCON2_TXDIS     0x2000
#define PHCON2_JABBER    0x0400
#define PHCON2_HDLDIS    0x0100

// ENC28J60 Packet Control Byte Bit Definitions
#define PKTCTRL_PHUGEEN  0x08
#define PKTCTRL_PPADEN   0x04
#define PKTCTRL_PCRCEN   0x02
#define PKTCTRL_POVERRIDE 0x01

// SPI operation codes
#define ENC28J60_READ_CTRL_REG       0x00
#define ENC28J60_READ_BUF_MEM        0x3A
#define ENC28J60_WRITE_CTRL_REG      0x40
#define ENC28J60_WRITE_BUF_MEM       0x7A
#define ENC28J60_BIT_FIELD_SET       0x80
#define ENC28J60_BIT_FIELD_CLR       0xA0
#define ENC28J60_SOFT_RESET          0xFF

// The RXSTART_INIT must be zero. See Rev. B4 Silicon Errata point 5.
// Buffer boundaries applied to internal 8K ram
// the entire available packet buffer space is allocated

#define RXSTART_INIT        0x0000  // start of RX buffer, room for 2 packets
#define RXSTOP_INIT         0x0BFF  // end of RX buffer

#define TXSTART_INIT        0x0C00  // start of TX buffer, room for 1 packet
#define TXSTOP_INIT         0x11FF  // end of TX buffer

#define SCRATCH_START       0x1200  // start of scratch area
#define SCRATCH_LIMIT       0x2000  // past end of area, i.e. 3.5 Kb
#define SCRATCH_PAGE_SHIFT  6       // addressing is in pages of 64 bytes
#define SCRATCH_PAGE_SIZE   (1 << SCRATCH_PAGE_SHIFT)

// max frame length which the conroller will accept:
// (note: maximum ethernet frame length would be 1518)
// 1500 - Payload
// add 14 Bytes for MAC header
// add 4 Bytes for VLAN header
#define MAX_FRAMELEN 1514

#define FULL_SPEED  1   // switch to full-speed SPI for bulk transfers

static byte Enc28j60Bank;
static int gNextPacketPtr;
static byte selectPin;

void ENC28J60::initSPI () {
    pinMode(SS, OUTPUT);
    digitalWrite(SS, HIGH);
    pinMode(MOSI, OUTPUT);
    pinMode(SCK, OUTPUT);
    pinMode(MISO, INPUT);

    digitalWrite(MOSI, HIGH);
    digitalWrite(MOSI, LOW);
    digitalWrite(SCK, LOW);

    SPCR = bit(SPE) | bit(MSTR); // 8 MHz @ 16
    bitSet(SPSR, SPI2X);
}

static void enableChip () {
    cli();
    digitalWrite(selectPin, LOW);
}

static void disableChip () {
    digitalWrite(selectPin, HIGH);
    sei();
}

static void xferSPI (byte data) {
    SPDR = data;
    while (!(SPSR&(1<<SPIF)))
        ;
}

static byte readOp (byte op, byte address) {
    enableChip();
    xferSPI(op | (address & ADDR_MASK));
    xferSPI(0x00);
    if (address & 0x80)
        xferSPI(0x00);
    byte result = SPDR;
    disableChip();
    return result;
}

static void writeOp (byte op, byte address, byte data) {
    enableChip();
    xferSPI(op | (address & ADDR_MASK));
    xferSPI(data);
    disableChip();
}

static void readBuf(uint16_t len, byte* data) {
    enableChip();
    xferSPI(ENC28J60_READ_BUF_MEM);
    while (len--) {
        xferSPI(0x00);
        *data++ = SPDR;
    }
    disableChip();
}

static void writeBuf(uint16_t len, const byte* data) {
    enableChip();
    xferSPI(ENC28J60_WRITE_BUF_MEM);
    while (len--)
        xferSPI(*data++);
    disableChip();
}

static void SetBank (byte address) {
    if ((address & BANK_MASK) != Enc28j60Bank) {
        writeOp(ENC28J60_BIT_FIELD_CLR, ECON1, ECON1_BSEL1|ECON1_BSEL0);
        Enc28j60Bank = address & BANK_MASK;
        writeOp(ENC28J60_BIT_FIELD_SET, ECON1, Enc28j60Bank>>5);
    }
}

static byte readRegByte (byte address) {
    SetBank(address);
    return readOp(ENC28J60_READ_CTRL_REG, address);
}

static uint16_t readReg(byte address) {
    return readRegByte(address) + (readRegByte(address+1) << 8);
}

static void writeRegByte (byte address, byte data) {
    SetBank(address);
    writeOp(ENC28J60_WRITE_CTRL_REG, address, data);
}

static void writeReg(byte address, uint16_t data) {
    writeRegByte(address, data);
    writeRegByte(address + 1, data >> 8);
}

static uint16_t readPhyByte (byte address) {
    writeRegByte(MIREGADR, address);
    writeRegByte(MICMD, MICMD_MIIRD);
    while (readRegByte(MISTAT) & MISTAT_BUSY)
        ;
    writeRegByte(MICMD, 0x00);
    return readRegByte(MIRD+1);
}

static void writePhy (byte address, uint16_t data) {
    writeRegByte(MIREGADR, address);
    writeReg(MIWR, data);
    while (readRegByte(MISTAT) & MISTAT_BUSY)
        ;
}

byte ENC28J60::initialize (uint16_t size, const byte* macaddr, byte csPin) {
    bufferSize = size;
    if (bitRead(SPCR, SPE) == 0)
        initSPI();
    selectPin = csPin;
    pinMode(selectPin, OUTPUT);
    disableChip();

    writeOp(ENC28J60_SOFT_RESET, 0, ENC28J60_SOFT_RESET);
    delay(2); // errata B7/2
    
    unsigned long st = millis();
    while (!readOp(ENC28J60_READ_CTRL_REG, ESTAT) & ESTAT_CLKRDY) {
      if (millis() > st+30000L) return 0;  // 30 seconds timeout
    }
    
    gNextPacketPtr = RXSTART_INIT;
    writeReg(ERXST, RXSTART_INIT);
    writeReg(ERXRDPT, RXSTART_INIT);
    writeReg(ERXND, RXSTOP_INIT);
    writeReg(ETXST, TXSTART_INIT);
    writeReg(ETXND, TXSTOP_INIT);
    enableBroadcast(); // change to add ERXFCON_BCEN recommended by epam
    writeReg(EPMM0, 0x303f);
    writeReg(EPMCS, 0xf7f9);
    writeRegByte(MACON1, MACON1_MARXEN|MACON1_TXPAUS|MACON1_RXPAUS);
    writeRegByte(MACON2, 0x00);
    writeOp(ENC28J60_BIT_FIELD_SET, MACON3,
            MACON3_PADCFG0|MACON3_TXCRCEN|MACON3_FRMLNEN);
    writeReg(MAIPG, 0x0C12);
    writeRegByte(MABBIPG, 0x12);
    writeReg(MAMXFL, MAX_FRAMELEN);
    writeRegByte(MAADR5, macaddr[0]);
    writeRegByte(MAADR4, macaddr[1]);
    writeRegByte(MAADR3, macaddr[2]);
    writeRegByte(MAADR2, macaddr[3]);
    writeRegByte(MAADR1, macaddr[4]);
    writeRegByte(MAADR0, macaddr[5]);
    writePhy(PHCON2, PHCON2_HDLDIS);
    SetBank(ECON1);
    writeOp(ENC28J60_BIT_FIELD_SET, EIE, EIE_INTIE|EIE_PKTIE);
    writeOp(ENC28J60_BIT_FIELD_SET, ECON1, ECON1_RXEN);

    byte rev = readRegByte(EREVID);
    // microchip forgot to step the number on the silcon when they
    // released the revision B7. 6 is now rev B7. We still have
    // to see what they do when they release B8. At the moment
    // there is no B8 out yet
    if (rev > 5) ++rev;
    return rev;
}

bool ENC28J60::isLinkUp() {
    return (readPhyByte(PHSTAT2) >> 2) & 1;
}

void ENC28J60::packetSend(uint16_t len) {
    // see http://forum.mysensors.org/topic/536/
    // while (readOp(ENC28J60_READ_CTRL_REG, ECON1) & ECON1_TXRTS)
        if (readRegByte(EIR) & EIR_TXERIF) {
            writeOp(ENC28J60_BIT_FIELD_SET, ECON1, ECON1_TXRST);
            writeOp(ENC28J60_BIT_FIELD_CLR, ECON1, ECON1_TXRST);
            writeOp(ENC28J60_BIT_FIELD_CLR, EIR, EIR_TXERIF);
        }
    writeReg(EWRPT, TXSTART_INIT);
    writeReg(ETXND, TXSTART_INIT+len);
    writeOp(ENC28J60_WRITE_BUF_MEM, 0, 0x00);
    writeBuf(len, buffer);
    writeOp(ENC28J60_BIT_FIELD_SET, ECON1, ECON1_TXRTS);
}
/*
void ENC28J60::packetSend(uint16_t len) {
    while (readOp(ENC28J60_READ_CTRL_REG, ECON1) & ECON1_TXRTS)
        if (readRegByte(EIR) & EIR_TXERIF) {
            writeOp(ENC28J60_BIT_FIELD_SET, ECON1, ECON1_TXRST);
            writeOp(ENC28J60_BIT_FIELD_CLR, ECON1, ECON1_TXRST);
        }
    writeReg(EWRPT, TXSTART_INIT);
    writeReg(ETXND, TXSTART_INIT+len);
    writeOp(ENC28J60_WRITE_BUF_MEM, 0, 0x00);
    writeBuf(len, buffer);
    writeOp(ENC28J60_BIT_FIELD_SET, ECON1, ECON1_TXRTS);
}
*/
uint16_t ENC28J60::packetReceive() {
    uint16_t len = 0;
    if (readRegByte(EPKTCNT) > 0) {
        writeReg(ERDPT, gNextPacketPtr);

        struct {
            uint16_t nextPacket;
            uint16_t byteCount;
            uint16_t status;
        } header;

        readBuf(sizeof header, (byte*) &header);

        gNextPacketPtr  = header.nextPacket;
        len = header.byteCount - 4; //remove the CRC count
        if (len>bufferSize-1)
            len=bufferSize-1;
        if ((header.status & 0x80)==0)
            len = 0;
        else
            readBuf(len, buffer);
        buffer[len] = 0;
        if (gNextPacketPtr - 1 > RXSTOP_INIT)
            writeReg(ERXRDPT, RXSTOP_INIT);
        else
            writeReg(ERXRDPT, gNextPacketPtr - 1);
        writeOp(ENC28J60_BIT_FIELD_SET, ECON2, ECON2_PKTDEC);
    }
    return len;
}

void ENC28J60::copyout (byte page, const byte* data) {
    uint16_t destPos = SCRATCH_START + (page << SCRATCH_PAGE_SHIFT);
    if (destPos < SCRATCH_START || destPos > SCRATCH_LIMIT - SCRATCH_PAGE_SIZE)
        return;
    writeReg(EWRPT, destPos);
    writeBuf(SCRATCH_PAGE_SIZE, data);
}

void ENC28J60::copyin (byte page, byte* data) {
    uint16_t destPos = SCRATCH_START + (page << SCRATCH_PAGE_SHIFT);
    if (destPos < SCRATCH_START || destPos > SCRATCH_LIMIT - SCRATCH_PAGE_SIZE)
        return;
    writeReg(ERDPT, destPos);
    readBuf(SCRATCH_PAGE_SIZE, data);
}

byte ENC28J60::peekin (byte page, byte off) {
    byte result = 0;
    uint16_t destPos = SCRATCH_START + (page << SCRATCH_PAGE_SHIFT) + off;
    if (SCRATCH_START <= destPos && destPos < SCRATCH_LIMIT) {
        writeReg(ERDPT, destPos);
        readBuf(1, &result);
    }
    return result;
}

// Contributed by Alex M. Based on code from: http://blog.derouineau.fr
//                  /2011/07/putting-enc28j60-ethernet-controler-in-sleep-mode/
void ENC28J60::powerDown() {
    writeOp(ENC28J60_BIT_FIELD_CLR, ECON1, ECON1_RXEN);
    while(readRegByte(ESTAT) & ESTAT_RXBUSY);
    while(readRegByte(ECON1) & ECON1_TXRTS);
    writeOp(ENC28J60_BIT_FIELD_SET, ECON2, ECON2_VRPS);
    writeOp(ENC28J60_BIT_FIELD_SET, ECON2, ECON2_PWRSV);
}

void ENC28J60::powerUp() {
    writeOp(ENC28J60_BIT_FIELD_CLR, ECON2, ECON2_PWRSV);
    while(!readRegByte(ESTAT) & ESTAT_CLKRDY);
    writeOp(ENC28J60_BIT_FIELD_SET, ECON1, ECON1_RXEN);
}

void ENC28J60::enableBroadcast (bool temporary) {
    writeRegByte(ERXFCON, readRegByte(ERXFCON) | ERXFCON_BCEN);
    if(!temporary)
        broadcast_enabled = true;
}

void ENC28J60::disableBroadcast (bool temporary) {
    if(!temporary)
        broadcast_enabled = false;
    if(!broadcast_enabled)
        writeRegByte(ERXFCON, readRegByte(ERXFCON) & ~ERXFCON_BCEN);
}

void ENC28J60::enableMulticast () {
    writeRegByte(ERXFCON, readRegByte(ERXFCON) | ERXFCON_MCEN);
}

void ENC28J60::disableMulticast () {
    writeRegByte(ERXFCON, readRegByte(ERXFCON) & ~ERXFCON_MCEN);
}

uint8_t ENC28J60::doBIST ( byte csPin) {
#define RANDOM_FILL        0b0000
#define ADDRESS_FILL    0b0100
#define PATTERN_SHIFT    0b1000
#define RANDOM_RACE        0b1100

// init
    if (bitRead(SPCR, SPE) == 0)
        initSPI();
    selectPin = csPin;
    pinMode(selectPin, OUTPUT);
    disableChip();

    writeOp(ENC28J60_SOFT_RESET, 0, ENC28J60_SOFT_RESET);
    delay(2); // errata B7/2
    while (!readOp(ENC28J60_READ_CTRL_REG, ESTAT) & ESTAT_CLKRDY) ;


    // now we can start the memory test

    uint16_t macResult;
    uint16_t bitsResult;

    // clear some of the registers registers
    writeRegByte(ECON1, 0);
    writeReg(EDMAST, 0);

    // Set up necessary pointers for the DMA to calculate over the entire memory
    writeReg(EDMAND, 0x1FFFu);
    writeReg(ERXND, 0x1FFFu);

    // Enable Test Mode and do an Address Fill
    SetBank(EBSTCON);
    writeRegByte(EBSTCON, EBSTCON_TME | EBSTCON_BISTST | ADDRESS_FILL);

    // wait for BISTST to be reset, only after that are we actually ready to
    // start the test
    // this was undocumented :(
    while (readOp(ENC28J60_READ_CTRL_REG, EBSTCON) & EBSTCON_BISTST);
    writeOp(ENC28J60_BIT_FIELD_CLR, EBSTCON, EBSTCON_TME);


    // now start the actual reading an calculating the checksum until the end is
    // reached
    writeOp(ENC28J60_BIT_FIELD_SET, ECON1, ECON1_DMAST | ECON1_CSUMEN);
    SetBank(EDMACS);
    while(readOp(ENC28J60_READ_CTRL_REG, ECON1) & ECON1_DMAST);
    macResult = readReg(EDMACS);
    bitsResult = readReg(EBSTCS);
    // Compare the results
    // 0xF807 should always be generated in Address fill mode
    if ((macResult != bitsResult) || (bitsResult != 0xF807)) {
        return 0;
    }
    // reset test flag
    writeOp(ENC28J60_BIT_FIELD_CLR, EBSTCON, EBSTCON_TME);


    // Now start the BIST with random data test, and also keep on swapping the
    // DMA/BIST memory ports.
    writeRegByte(EBSTSD, 0b10101010 | millis());
    writeRegByte(EBSTCON, EBSTCON_TME | EBSTCON_PSEL | EBSTCON_BISTST | RANDOM_FILL);


    // wait for BISTST to be reset, only after that are we actually ready to
    // start the test
    // this was undocumented :(
    while (readOp(ENC28J60_READ_CTRL_REG, EBSTCON) & EBSTCON_BISTST);
    writeOp(ENC28J60_BIT_FIELD_CLR, EBSTCON, EBSTCON_TME);


    // now start the actual reading an calculating the checksum until the end is
    // reached
    writeOp(ENC28J60_BIT_FIELD_SET, ECON1, ECON1_DMAST | ECON1_CSUMEN);
    SetBank(EDMACS);
    while(readOp(ENC28J60_READ_CTRL_REG, ECON1) & ECON1_DMAST);

    macResult = readReg(EDMACS);
    bitsResult = readReg(EBSTCS);
    // The checksum should be equal
    return macResult == bitsResult;
}