Serial FT1.2 first write fails after reset/reboot

[tllngr]

Baos SDK fails on the very first write attempt after baos chip/module has performed a reboot caused by ETS action.

Steps to reproduce:

• Baos 83x starter kit connected via USB on PC (Linux host)

• Configure Baos 83x via ETS, Datapoint ID=1, DPT=1(boolean)

• Using following sample application to perform cyclic write action to datapoint:

//based on sample "BaosSerial.cpp"
#include <kdrive/baos/Baos.h>
#include <kdrive/connector/CallbackThread.h>
#include <kdrive/utility/Logger.h>
#include <kdrive/utility/LoggerFormatter.h>
#include <Poco/Exception.h>
#include <Poco/Format.h>
#include <iostream>

using namespace kdrive::baos;
using namespace kdrive::connector;
using namespace kdrive::utility;
using Poco::Exception;
using Poco::format;

CLASS_LOGGER("BaosSerial")

int main(int argc, char *argv[])
{
  // configure the logging channel
  INIT_ROOT_CONSOLE_LOGGER();
  Poco::Logger::root().setLevel("debug");
  Poco::Logger::get("kdrive.io.serial.SerialPort").setLevel("error");

  try {
    // connects the BAOS FT 1.2 Module
    FT12Connector::Ptr connector = std::make_shared<FT12Connector>();
    connector->open("/dev/ttyUSB0");

    // get the Serial Number
    BaosServerItems baosServerItems(connector);
    poco_information(LOGGER(),
        format("Serial Number: %s",
            LoggerFormatter::toHex(baosServerItems.getSerialNumber())));

    while (true) {
      BaosDatapoint dp(connector, 1);
      dp.setBoolean(true);
      sleep(3);
    }
  } catch (Exception &exception) {
    LOGGER().log(exception);
  }

  return EXIT_SUCCESS;
}

• Run application. Cyclic write to datapoint is performed as expected
• Perform a device reset via ETS
• Depending on ft1.2 CI field byte (FCB/FCV) communication fails and exception is thrown. See following log:

13:02:33:344 [kdrive.ft12.FT12_Packetizer] ft1.2 rx: 68 0B 0B 68 F3 F0 C2 00 0A 00 01 00 0A 01 00 BB 16
13:02:33:344 [kdrive.ft12.FT12] Rx invalid FT1.2 variable frame
13:02:33:373 [kdrive.ft12.FT12_Packetizer] ft1.2 tx: E5
13:02:33:373 [kdrive.ft12.FT12_Packetizer] ft1.2 rx: 68 0B 0B 68 D3 F0 C2 00 0A 00 01 00 0A 01 01 9C 16
13:02:36:681 [kdrive.ft12.FT12_Packetizer] ft1.2 tx: 68 0C 0C 68 53 F0 06 00 01 00 01 00 01 03 01 01 51 16
13:02:36:705 [kdrive.ft12.FT12_Packetizer] ft1.2 rx: E5
13:02:41:706 [kdrive.connector.CallbackThread] Callback thread stop requested [id 2, QueueConnector Rx]
13:02:41:716 [kdrive.connector.CallbackThread] Callback thread stopped [id 2, name QueueConnector Rx]
13:02:41:719 [kdrive.connector.CallbackThread] Callback thread stop requested [id 1, AsyncConnectorNotificationHandler]
13:02:41:720 [kdrive.connector.CallbackThread] Callback thread stopped [id 1, name AsyncConnectorNotificationHandler]
13:02:41:720 [BaosSerial] Timeout

Reason of issue

Cause of the issue is a bug at FT12_Packetizer::readBytes function. Return type of FT12_Packetizer::readBytes is boolean instead of std::size_t. This leads to FT12_Packetizer::readFixedFrame failing to get the correct number of bytes read when Reset.Ind 0x10 0xC0 0xC0 0x16 was received due to reset.

//FIXME: Length is determined from bool returned by readBytes
std::size_t length = readBytes(ptr + 1, bufferSize - 1, FixedLengthFrame::Length - 1, shortTimeout) + 1;

Bugfix

Fix FT1.2_Packetizer like so:

FT12_Packetizer.h

• Change return type from bool to std::size_t

  std::size_t readBytes(char* buffer, std::size_t bufferSize, std::size_t bytesToRead, long timeout);

FT12_Packetizer.cpp

• Change return type of FT12_Packetizer::readBytes from bool to std::size_t

• Return length instead of boolean condition bytesToRead ? true : false at FT12_Packetizer::readBytes

  std::size_t FT12_Packetizer::readBytes(char* buffer, std::size_t bufferSize, std::size_t bytesToRead, long timeout)
  {
  BOOST_ASSERT(bytesToRead <= bufferSize && "Buffer Overflow");
  
  std::size_t length = 0;
  while ((length < bytesToRead) && serialPort_.poll(timeout))
  {
      const std::size_t n = serialPort_.read(buffer + length, bytesToRead - length);
  
      if (n > 0)
      {
          length += n;
      }
  }
  
  return length;
  }

• FT12_Packetizer::get: Change ternary condition to fit new return type of FT12_Packetizer::readBytes

  //FT12_Packetizer::get
  const std::size_t length = (readBytes(ptr, bufferSize, 1, timeout_) == 1) ? readFrame(buffer, bufferSize) : 0;

After the fix, the Reset.Ind appears in log and is handled correctly by resetting FCB/FCV:

13:07:16:224 [kdrive.ft12.FT12_Packetizer] ft1.2 rx: 10 C0 C0 16
13:07:16:736 [kdrive.ft12.FT12_Packetizer] ft1.2 tx: E5
13:07:16:736 [kdrive.ft12.FT12_Packetizer] ft1.2 rx: 68 0B 0B 68 F3 F0 C2 00 0A 00 01 00 0A 01 00 BB 16
13:07:16:752 [kdrive.ft12.FT12_Packetizer] ft1.2 tx: E5
13:07:16:752 [kdrive.ft12.FT12_Packetizer] ft1.2 rx: 68 0B 0B 68 D3 F0 C2 00 0A 00 01 00 0A 01 01 9C 16
13:07:17:254 [kdrive.ft12.FT12_Packetizer] ft1.2 tx: 68 0C 0C 68 73 F0 06 00 01 00 01 00 01 03 01 01 71 16
13:07:17:277 [kdrive.ft12.FT12_Packetizer] ft1.2 rx: E5
13:07:17:294 [kdrive.ft12.FT12_Packetizer] ft1.2 tx: E5
13:07:17:294 [kdrive.ft12.FT12_Packetizer] ft1.2 rx: 68 08 08 68 F3 F0 86 00 01 00 00 00 6A 16