/// <summary>
/// Request to read bytes from memory map
/// </summary>
/// <param name="serial">A double precision number.</param>
/// <param name="addres">A double precision number.</param>
/// <param name="bytesToRead">A double precision number.</param>
/// <param name="timeut">A double precision number.</param>
/// <returns>
/// Memory Map values from read address request
/// </returns>
/// <example>
/// <code>
/// lx.Read(new USBSerial("COM5"), 0, 1, 400)
/// </code>
/// </example>
/// <exception cref="System.TimeoutException">Thrown response Timeout is reached </exception>
/// <exception cref="System.IO.InvalidDataException">Thrown when response data or CRC is not valid </exception>
/// See <see cref="Read(UInt32 addres, uint data)"/> to add doubles.
/// <seealso cref="Write(byte addres, byte[] data)"/>
/// <seealso cref="Write(ISerial serial, UInt32 addres, byte[] data, int timeout)"/>
private async Task <byte[]> Read(ISerial serial, UInt32 address, uint bytesToRead, int timeout)
{
int TEST = new Random().Next(0, 999);
Utils.PrintDeep(Environment.NewLine + "--------LEXI_READ-------| " + TEST + " |--");
Utils.PrintDeep("Lexi.Read = Write + UpdateBuffer + Read");
try
{
byte[] stream;
var info = GeneratePackage(LexiAction.Read, out stream, address, null, bytesToRead);
Utils.PrintDeep("Lexi.Read.. " +
"Stream = " +
"0x" + info.header + " ( " + Convert.ToInt32(info.header, 16) + " ) + " +
"WriteCmd 0x" + info.cmd + " ( " + Convert.ToInt32(info.cmd, 16) + " ) + " +
"Address 0x" + info.startAddress + " ( " + Convert.ToInt32(info.startAddress, 16) + " ) + " +
"Checksum 0x" + info.checksum + " ( " + Convert.ToInt32(info.checksum, 16) + " )");
Utils.PrintDeep("Lexi.Read.. " + Utils.ByteArrayToString(stream).Trim() + " [ Length " + stream.Length + " ]");
// Send Lexi Read command
await serial.Write(stream, 0, stream.Length);
Utils.PrintDeep("------BUFFER_START-------");
//define response buffer size
byte[] rawBuffer = new byte[0];
int headerOffset = (serial.isEcho()) ? stream.Length : 0;
Array.Resize(ref rawBuffer, headerOffset + ( int )bytesToRead + 2); // Package + Data + ACK
Utils.PrintDeep("Lexi.Read -> Array.Resize.." +
" Echo " + serial.isEcho() +
" [ " + rawBuffer.Length + " = " + bytesToRead + " + Header " + headerOffset + " + CRC 2 ]");
// Whait untill the response buffer data is available or timeout limit is reached
long timeout_limit = DateTimeOffset.Now.ToUnixTimeMilliseconds() + (timeout);
await Task.Run(() =>
{
while (checkResponseOk(serial, rawBuffer))
{
if (DateTimeOffset.Now.ToUnixTimeMilliseconds() > timeout_limit)
{
int num = serial.BytesReadCount();
Utils.PrintDeep("Lexi.Read -> BytesToRead: " + num);
if (num <= headerOffset)
{
Utils.PrintDeep("Lexi.Read -> CheckResponseOk IOException");
throw new IOException();
}
else
{
Utils.PrintDeep("Lexi.Read -> CheckResponseOk TimeoutException");
throw new TimeoutException();
}
}
Thread.Sleep(10);
}
});
Utils.PrintDeep("------BUFFER_FINISH------");
//read the response buffer
serial.Read(rawBuffer, 0, rawBuffer.Length);
/*
* +------------+-------+---------------+--------------------------------------------------------+
* | Byte Index | Field | Value(s) | Notes |
* +------------+-------+---------------+--------------------------------------------------------+
* | 0..N-1 | Data | Read from RAM | N = number of bytes specified in Data field of Request |
* | N..N+1 | CRC | Calculated | CRC over all data bytes. See section 7.2 |
* +------------+-------+---------------+--------------------------------------------------------+
*/
// Removes header and get only the ACK
byte[] response = new byte[2];
Array.Resize(ref response, response.Length + ( int )bytesToRead);
Array.Copy(rawBuffer, headerOffset, response, 0, response.Length);
Utils.PrintDeep("Lexi.Read ->" +
" CheckCRC " + Utils.ByteArrayToString(response) +
" [ " + response.Length + " = BytesToRead " + bytesToRead + " + ACK 2 ]");
// Validates CRC and if everything is ok, returns recovered data
return(validateReadResponse(response, bytesToRead));
}
catch (Exception e)
{
throw new LexiReadingException();
}
finally
{
Utils.PrintDeep("----LEXI_READ_FINISH----| " + TEST + " |--" + Environment.NewLine);
}
}