/// <summary>
/// Sends the packet.
/// </summary>
/// <param name="data">The data.</param>
/// <returns></returns>
public bool SendPacket(byte[] data)
{
uint txd = nextTXDesc++;
if (nextTXDesc >= 16)
{
nextTXDesc = 0;
}
uint offset = txd * 4;
// check if (oldest) descriptor is available (Bit 31/OWN = 0 available)
if ((txDescriptor.Read32(offset + 1) & 0x80000000) == 0)
{
for (uint i = 0; i < data.Length; i++)
{
buffers.Write8((txd * bufferSize) + i, data[i]);
}
ushort length = (ushort)(~data.Length);
length++;
// Set bits 31/OWN, 25/STP (start of packet), 24/ENP (end of packet) and two's compliment of the buffer length
txDescriptor.Write32(offset + 1, (length & (uint)(0x0FFF)) | (uint)(0x8300F000));
return(true);
}
return(false);
}
/// <summary>
/// Retrieves the packets.
/// </summary>
protected void RetrievePackets()
{
// Check all descriptors
for (uint rxd = 0; rxd < 16; rxd++)
{
uint offset = rxd * 4;
uint status = rxDescriptor.Read32(offset + 1);
// Check is 31/OWN bit is not set
if ((status & 0x80000000) == 0)
{
ushort length = (ushort)(rxDescriptor.Read16(offset + 0) & 0xFFF);
var data = new byte[length];
for (uint i = 0; i < data.Length; i++)
{
data[i] = buffers.Read8((rxd * bufferSize) + i);
}
// if queue fails because it is already full, the packet is discarded
packetBuffer.QueuePacketForStack(data);
// Clear 31/OWN bit
rxDescriptor.Write32(offset + 1, status | 0x80000000);
}
}
}
/// <summary>
/// Gets the fifo.
/// </summary>
/// <param name="index">The index.</param>
/// <returns></returns>
protected uint GetFifo(uint index)
{
return(fifo.Read32(index * 4));
}