Writes get truncated at 255 characters

[hb020]

I can't believe I didn't catch this earlier. This is a serious and trivial bug for my use, where I can send much more than 255 characters.

Prologix is limited to 127 characters in the present implementation, and will have all kinds of problems when you get over that limit: You'll get an EOI in the middle of a command, etc.
I'm not addressing that issue for now, I'm addressing the issue for my use case.

Simple uint8_t to uint16_t change.

void GPIBbus::sendData(const char *data, uint8_t dsize, bool isLastPacket)

should be

void GPIBbus::sendData(const char *data, uint16_t dsize, bool isLastPacket)

And while you're at it, you may want to do this in sendData():

#ifdef DEBUG_GPIBbus_SEND
    DB_RAW_PRINT(data[i]);
#endif

    if (state != HANDSHAKE_COMPLETE) break;
  }

#ifdef DEBUG_GPIBbus_SEND
  DB_PRINT(F("<- End of send loop."), "");
#endif

does not catch an abort. It is better when you do this:

#ifdef DEBUG_GPIBbus_SEND
    DB_RAW_PRINT(data[i]);
#endif

    if (state != HANDSHAKE_COMPLETE) {
#ifdef DEBUG_GPIBbus_SEND
      DB_RAW_PRINT("\n");
      DB_PRINT(F("ERR: Writing aborted at character "), i);
      DB_PRINT(F("End of send loop. State: "), state);
#endif
      break;
    }
  }

#ifdef DEBUG_GPIBbus_SEND
  DB_RAW_PRINT("\n");
  DB_PRINT(F("<- End of send loop."), "");
#endif

[Twilight-Logic]

Ok, this is going back a bit. The original premise, I think was that on 8-bit AVR boards like the UNO you couldn't have a very big buffer, so it was not likely to exceed 256 bytes and I just copied Prologix and used 128 bytes (127 taking into account the final null). The serial buffer on an 8-bit AVR is actually only 64 bytes. To a controller one would be sending mostly commands a line at a time so that would be rarely exceeded. On clone boards this is a problem because there is no handshaking so you end up with garbage if the data is too long or sent too fast. Boards with FTDI, 16u2 (FTDI emulation) and 32u4 (CDC) do have handshaking so could cope. In any case, thinking of conserving dynamic memory usage, the smallest variable type was used requiring just one 8-bit byte.

However, on other (16 & 32bit) plaforms you have more resources so it is possible to allocate a larger buffer. I think the easiest would be to use size_t, as the compiler will use at least 16bit or whatever is appropriate for the platform.

[Twilight-Logic]

I have changed this in the latest release (0.53.56) and updated the debug statements in sendData().