cs8900a.c

CS8900 ethernet driver for LPC210x

  IOCLR = 0x0f << ADDR_SHIFT;			// Put address on bus
  IOSET = addr << ADDR_SHIFT;		
  IOCLR = 0xff << DATA_SHIFT;			// Write low order byte to data bus
  IOSET = (data & 0xff) << DATA_SHIFT;		
  
  IOCLR = IOW;                      	// Toggle IOW-signal
  IOWAIT();
  IOSET = IOW;

  IOCLR = 0x0f << ADDR_SHIFT;
  IOSET = ((addr | 1) << ADDR_SHIFT);	// And put next address on bus

  IOCLR = 0xff << DATA_SHIFT;           // Write high order byte to data bus
  IOSET = ((data >> 8) & 0xff) << DATA_SHIFT;

  IOCLR = IOW;                          // Toggle IOW-signal
  IOWAIT();
  IOSET = IOW;
}

// Reads a word in little-endian byte order from a specified port-address
unsigned
cs8900a_read(unsigned addr)
{
  unsigned int value;

  CS(CS_CS8900A);						// select the ethernet device
  
  IODIR &= ~(0xff << DATA_SHIFT);       // Data port to input

  IOCLR = 0x0f << ADDR_SHIFT;           // Put address on bus
  IOSET = addr << ADDR_SHIFT;

  IOCLR = IOR;                          // IOR-signal low
  value = (IOPIN >> DATA_SHIFT) & 0xff; // get low order byte from data bus
  IOSET = IOR;

  IOSET = 1 << ADDR_SHIFT;              // IOR high and put next address on bus

  IOCLR = IOR;                          // IOR-signal low
  value |= (((IOPIN >> DATA_SHIFT) << 8) & 0xff00);	// get high order byte from data bus
  IOSET = IOR;                          // IOR-signal low
  
  return value;
}

// Reads a word in little-endian byte order from a specified port-address
unsigned
cs8900a_read_addr_high_first(unsigned addr)
{
  unsigned int value;

  CS(CS_CS8900A);						// select the ethernet device
  
  IODIR &= ~(0xff << DATA_SHIFT);		// Data port to input

  IOCLR = 0x0f << ADDR_SHIFT;           // Put address on bus
  IOSET = (addr+1) << ADDR_SHIFT;

  IOCLR = IOR;                          // IOR-signal low
  IOWAIT();
  value = (((IOPIN >> DATA_SHIFT) << 8) & 0xff00);	// get high order byte from data bus
  IOSET = IOR;                          // IOR-signal high

  IOCLR = 1 << ADDR_SHIFT;              // Put low address on bus

  IOCLR = IOR;                          // IOR-signal low
  IOWAIT();
  value |= (IOPIN >> DATA_SHIFT) & 0xff;// get low order byte from data bus
  IOSET = IOR;

  return value;
}

void
cs8900a_init(void)
{
  int i;

  ticks = 0;
  CS(CS_CS8900A);						// select the ethernet device
  
  // Reset outputs, control lines high
  IOSET  = IOR | IOW;
  IODIR |= IOR | IOW;

  // No LEDs on.
  IOSET  = LED_RED | LED_YELLOW | LED_GREEN;
  IODIR |= LED_RED | LED_YELLOW | LED_GREEN;

  //IODIR |= 0xff << DATA_SHIFT;
  IODIR |= 0x0f << ADDR_SHIFT;

  // Reset outputs
  //IOCLR = 0xff << DATA_SHIFT;			// clear data outputs

  // Reset the CS8900A
  cs8900a_write(ADD_PORT, PP_SelfCTL);
  cs8900a_write(DATA_PORT, POWER_ON_RESET);

  // Wait until chip-reset is done
  cs8900a_write(ADD_PORT, PP_SelfST);
  while ((cs8900a_read(DATA_PORT) & INIT_DONE) == 0)
    ;

  // Configure the CS8900A
  for (i = 0; i < sizeof InitSeq / sizeof (TInitSeq); ++i)
    {
      cs8900a_write(ADD_PORT, InitSeq[i].Addr);
      cs8900a_write(DATA_PORT, InitSeq[i].Data);
    }
}

void
cs8900a_send(void)
{
  unsigned u;

  CS(CS_CS8900A);								// select the ethernet device
  
  IOCLR = LED_RED;  // Light RED LED when frame starting

  // Transmit command
  cs8900a_write(TX_CMD_PORT, TX_START_ALL_BYTES);
  cs8900a_write(TX_LEN_PORT, uip_len);

  // Maximum number of retries
  u = 8;
  for (;;)
    {
      // Check for avaliable buffer space
      cs8900a_write(ADD_PORT, PP_BusST);
      if (cs8900a_read(DATA_PORT) & READY_FOR_TX_NOW)
        break;
      if (u -- == 0)
        {
          IOSET = LED_RED;  // Extinguish RED LED on end of frame
          return;
        }

      // No space avaliable, skip a received frame and try again
      skip_frame();
    }

  IODIR |= 0xff << DATA_SHIFT;			// Data port to output

  // Send 40+14=54 bytes of header
  for (u = 0; u < 54; u += 2)
    {
      IOCLR = 0xf << ADDR_SHIFT;        // Put address on bus
      IOSET = TX_FRAME_PORT << ADDR_SHIFT;

      IOCLR = 0xff << DATA_SHIFT;		// Write low order byte to data bus
      IOSET = (uip_buf[u] & 0xff) << DATA_SHIFT;	// write low order byte to data bus

      IOCLR = IOW;						// Toggle IOW-signal
      IOWAIT();
      IOSET = IOW;

      IOCLR = 0x0f << ADDR_SHIFT;		// Put address on bus
      IOSET = (TX_FRAME_PORT | 1) << ADDR_SHIFT;	// and put next address on bus

      IOCLR = 0xff << DATA_SHIFT;        // Write low order byte to data bus
      IOSET = (uip_buf[u+1] & 0xff) << DATA_SHIFT;// write low order byte to data bus

      IOCLR = IOW;                       // Toggle IOW-signal
      IOWAIT();
      IOSET = IOW;
    }

  if (uip_len <= 54)
    {
      IOSET = LED_RED;  // Extinguish RED LED on end of frame
      return;
    }

  // Send remainder of packet, the application data
  uip_len -= 54;
  for (u = 0; u < uip_len; u += 2)
    {

      IOCLR = 0x0f << ADDR_SHIFT;		// Put address on bus
      IOSET = TX_FRAME_PORT << ADDR_SHIFT;

      IOCLR = 0xff << DATA_SHIFT; 		// Write low order byte to data bus
      IOSET = (uip_appdata[u] & 0xff) << DATA_SHIFT;	// write low order byte to data bus

      IOCLR = IOW;						// Toggle IOW-signal
	  IOWAIT();
      IOSET = IOW;

      IOCLR = 0x0f << ADDR_SHIFT;		// Put address on bus
      IOSET = (TX_FRAME_PORT | 1) << ADDR_SHIFT;	// and put next address on bus

      IOCLR = 0xff << DATA_SHIFT;		// Write low order byte to data bus
      IOSET = (uip_appdata[u+1] & 0xff) << DATA_SHIFT;	// write low order byte to data bus

      IOCLR = IOW;                      // Toggle IOW-signal
	  IOWAIT();
      IOSET = IOW;
    }
  IOSET = LED_RED;  					// Extinguish RED LED on end of frame
}

static void
skip_frame(void)
{
  // No space avaliable, skip a received frame and try again
  cs8900a_write(ADD_PORT, PP_RxCFG);
  cs8900a_write(DATA_PORT, cs8900a_read(DATA_PORT) | SKIP_1);
}

u8_t
cs8900a_poll(void)
{
  u16_t len, u, status;

  CS(CS_CS8900A);								// select the ethernet device
  
  // Check receiver event register to see if there are any valid frames avaliable
  cs8900a_write(ADD_PORT, PP_RxEvent);
  if ((status = (cs8900a_read(DATA_PORT) & 0xd00)) == 0)
    return 0;

  // Read receiver status and discard it.
  cs8900a_read_addr_high_first(RX_FRAME_PORT);

  // Read frame length
  if ((len = cs8900a_read_addr_high_first(RX_FRAME_PORT)) == 0)
  	return 0;		// ignore 0 length frames

  // If the frame is too big to handle, throw it away
  if (len > UIP_BUFSIZE)
    {
      skip_frame();
      return 0;
    }
    
  IOCLR = LED_GREEN;  					// Light GREED LED when frame coming in.
  
  // Data port to input
  IODIR &= ~(0xff << DATA_SHIFT);

  IOCLR = 0xf << ADDR_SHIFT;            // put address on bus
  IOSET = RX_FRAME_PORT << ADDR_SHIFT; 

  // Read bytes into uip_buf
  u = 0;
  while (u < len)
    {
      IOCLR = 1 << ADDR_SHIFT;          // put address on bus

      IOCLR = IOR;                      // IOR-signal low
      IOWAIT();
      uip_buf[u] = (IOPIN >> DATA_SHIFT) & 0xff;	// get high order byte from data bus
      IOSET = IOR;                      // IOR-signal high

      IOSET = 1 << ADDR_SHIFT;          // put address on bus

      IOCLR = IOR;                      // IOR-signal low
      IOWAIT();
      uip_buf[u+1] = (IOPIN >> DATA_SHIFT) & 0xff;	// get high order byte from data bus
      IOSET = IOR;                      // IOR-signal high
      u += 2;
    }

  IOSET = LED_GREEN;  // Extinguish GREED LED when frame finished.
  return len;
}

unsigned short
rt_ticks(void)
{
	// just return the ticks count
	return ticks;	
}