DE2 Ethernet Primitive Solution

hi,

I found there are some problem with the ReceivePacket function: I post my code:

unsigned int ReceivePacket (unsigned char *data_ptr,unsigned int *rx_len)

{

unsigned char rx_READY,GoodPacket;

unsigned char Tmp, RxStatus;

unsigned int high_b,low_b;

unsigned int i;

RxStatus = rx_len[0] = 0;

GoodPacket=FALSE;

/* mask NIC interrupts IMR: PAR only */

iow(IMR, PAR_set);

/* dummy read a byte from MRCMDX REG. F0H */

rx_READY = ior(MRCMDX);

/* got most updated byte: rx_READY */

rx_READY = IORD(DM9000A_BASE,IO_data)&0x03;

usleep(STD_DELAY);

/* reset the read pointer*/

Tmp = ior(0xF5);

printf("RD_P:0x%02X",Tmp);

Tmp = ior(0xF4);

printf("%02X\n",Tmp);

Tmp = ior(0x25);

printf("WR_P:0x%02X",Tmp);

Tmp = ior(0x24);

printf("%02X\n",Tmp);

/* check if (rx_READY == 0x01): Received Packet READY? */

if (rx_READY == DM9000_PKT_READY)

{

/* got RX_Status & RX_Length from RX SRAM */

IOWR(DM9000A_BASE, IO_addr, MRCMD); /* set MRCMD REG. F2H RX I/O port ready */

usleep(STD_DELAY);

IORD(DM9000A_BASE,IO_data); /*move pointer to status address*/

RxStatus = IORD(DM9000A_BASE,IO_data);

usleep(STD_DELAY);

low_b = IORD(DM9000A_BASE,IO_data);

high_b = IORD(DM9000A_BASE,IO_data);

rx_len[0] = high_b<<8;

rx_len[0] = rx_len[0]+low_b - 4;

/* Check this packet_status GOOD or BAD? */

if ( !(RxStatus & 0xBF) && (rx_len[0] < MAX_PACKET_SIZE) )

{

/* read 1 received packet from RX SRAM into RX buffer */

for (i = 0; i < rx_len[0]; i += 1)

{

usleep(STD_DELAY);

data_ptr[i] = IORD(DM9000A_BASE, IO_data);

}

/* dump the 4 BYTE FCS */

IORD(DM9000A_BASE, IO_data);

IORD(DM9000A_BASE, IO_data);

IORD(DM9000A_BASE, IO_data);

IORD(DM9000A_BASE, IO_data);

GoodPacket=TRUE;

} /* end if (GoodPacket) */

else

{

/* this packet is bad, dump it from RX SRAM */

for (i = 0; i < rx_len[0]; i += 1)

{

usleep(STD_DELAY);

Tmp = IORD(DM9000A_BASE, IO_data);

}

/* dump the 4 BYTE FCS */

IORD(DM9000A_BASE, IO_data);

IORD(DM9000A_BASE, IO_data);

IORD(DM9000A_BASE, IO_data);

IORD(DM9000A_BASE, IO_data);

printf("\nError\n");

rx_len[0] = 0;

} /* end if (!GoodPacket) */

} /* end if (rx_READY == DM9000_PKT_READY) ok */

else if(!rx_READY) /* status check first byte: rx_READY Bit[1:0] must be "00"b or "01"b */

{

/* software-RESET NIC */

iow(NCR, 0x03); /* NCR REG. 00 RST Bit [0] = 1 reset on, and LBK Bit [2:1] = 01b MAC loopback on */

usleep(20); /* wait > 10us for a software-RESET ok */

iow(NCR, 0x00); /* normalize */

iow(NCR, 0x03);

usleep(20);

iow(NCR, 0x00);

/* program operating registers~ */

iow(NCR, NCR_set); /* NCR REG. 00 enable the chip functions (and disable this MAC loopback mode back to normal) */

iow(0x08, BPTR_set); /* BPTR REG.08 (if necessary) RX Back Pressure Threshold in Half duplex moe only: High Water 3KB, 600 us */

iow(0x09, FCTR_set); /* FCTR REG.09 (if necessary) Flow Control Threshold setting High/ Low Water Overflow 5KB/ 10KB */

iow(0x0A, RTFCR_set); /* RTFCR REG.0AH (if necessary) RX/TX Flow Control Register enable TXPEN, BKPM (TX_Half), FLCE (RX) */

iow(0x0F, 0x00); /* Clear the all Event */

iow(0x2D, 0x80); /* Switch LED to mode 1 */

/* set other registers depending on applications */

iow(ETXCSR, ETXCSR_set); /* Early Transmit 75% */

/* enable interrupts to activate DM9000 ~on */

iow(IMR, INTR_set); /* IMR REG. FFH PAR=1 only, or + PTM=1& PRM=1 enable RxTx interrupts */

/* enable RX (Broadcast/ ALL_MULTICAST) ~go */

iow(RCR , RCR_set | RX_ENABLE | PASS_MULTICAST); /* RCR REG. 05 RXEN Bit [0] = 1 to enable the RX machine/ filter */

} /* end NIC H/W system Data-Bus error */

iow(ISR, 0x01);

iow(IMR, INTR_set);

// iow(0x0F, 0x00);

//iow(IMR, INTR_set);

return GoodPacket ? DMFE_SUCCESS : DMFE_FAIL;

}

I added the code(red), the problem you mentioned is solved.

the reason is MII added 4 byte FCS, When you read the packet, you should discard them, otherwise when you read the packet next time,you SRAM read pointer will point to the address less 4 byte than the right address,so it doesn't work.

I also find the receive packet function doesn't clear the interrupt and re enable the receive packet interrupt again, so I added the code for it.

Now ,you can try it , good luck