java - IOIO UART 读回问题

Question

我正在扩展 BaseIOIOLooper 以打开 UART 设备并发送消息。我正在使用回读进行测试，其中我通过一条线路发送一个数据包，并在另一条线路上接收该数据包并将其打印出来。因为我不希望 InputStream.read() 方法阻塞，所以我在不同的线程中处理数据包形成和输入。我已将问题范围缩小到 InputStream.read() 方法，该方法返回 -1 (没有读取字节，但也不异常(exception))。 这是 Looper 线程中的样子:

        @Override
    protected void setup() throws ConnectionLostException, InterruptedException {
        log_.write_log_line(log_header_ + "Beginning IOIO setup.");
        // Initialize IOIO UART pins
        // Input at pin 1, output at pin 2
        try {
            inQueue_ = MinMaxPriorityQueue.orderedBy(new ComparePackets())
                    .maximumSize(QUEUESIZE).create();
            outQueue_ = MinMaxPriorityQueue.orderedBy(new ComparePackets())
                    .maximumSize(QUEUESIZE).create();
            ioio_.waitForConnect();
            uart_ = ioio_.openUart(1, 2, 38400, Uart.Parity.NONE, Uart.StopBits.ONE);
            // Start InputHandler. Takes packets from ELKA on inQueue_
            in_= new InputHandler(inQueue_, uart_.getInputStream());
            in_.start();
            // Start OutputHandler. Takes packets from subprocesses on outQueue_
            out_= new OutputHandler(outQueue_);
            out_.start();
            // Get output stream
            os_=uart_.getOutputStream();
            // Set default target state
            setTargetState(State.TRANSFERRING);
            currInPacket_[0]=1; //Initial value to start transferring
            log_.write_log_line(log_header_ + "IOIO setup complete.\n\t" +
                    "Input pin set to 1\n\tOutput pin set to 2\n\tBaud rate set to 38400\n\t" +
                    "Parity set to even\n\tStop bits set to 1");
        } catch (IncompatibilityException e) {
            log_.write_log_line(log_header_+e.toString());
        } catch (ConnectionLostException e) {
            log_.write_log_line(log_header_+e.toString());
        } catch (Exception e) {
            log_.write_log_line(log_header_+"mystery exception: "+e.toString());
        }
    }

并且在InputHandler线程中:

    @Override
public void run() {
    boolean notRead;
    byte i;
    log_.write_log_line(log_header_+"Beginning InputHandler thread");
    while (!stop) {
        i = 0;
        notRead = true;
        nextInPacket = new byte[BUFFERSIZE];
        readBytes = -1;
        //StringBuilder s=new StringBuilder();
        //TODO re-implement this with signals
        while (i < READATTEMPTS && notRead) {
            try {
                // Make sure to adjust packet size. Done manually here for speed.
                readBytes = is_.read(nextInPacket, 0, BUFFERSIZE);
                /* Debugging
                for (int j=0;j<nextInPacket.length;j++)
                    s.append(Byte.toString(nextInPacket[j]));
                log_.write_log_line(log_header_+s.toString());
                */

                if (readBytes != -1) {
                    notRead = false;
                    nextInPacket= new byte[]{1,0,1,0,1,0,1,0,1,0,1,0,1,0,1,0};
                    synchronized (q_) {
                        q_.add(nextInPacket);
                    }
                //log_.write_log_line(log_header_ + "Incoming packet contains valid data.");
                } else i++;
            } catch (IOException e) {
                log_.write_log_line(log_header_ + "mystery exception:\n\t" + e.toString());
            }
        }

        if (i>=READATTEMPTS)
            log_.write_log_line(log_header_+"Too many read attempts from input stream.");

        /*
        try {
            sleep(100);
        } catch (InterruptedException e) {
            log_.write_log_line(log_header_+"fuck");
        }
        */
    }
}

在示波器上，引脚 1 和 2 都读取振荡电压，尽管幅度非常高，这是值得关注的。要点是无法从 InputHandler 类中的 InputStream 中读取任何内容。有什么想法吗？

Answer 1

从 read() 返回的

-1 仅应在 UART 关闭时发生。在 Uart 对象上显式调用 close() 或在 IOIO 对象上调用 softReset() 可能会导致关闭。

Android 日志可能会为您提供一些有关正在发生的情况的线索。

您在示波器上看到的读数很可疑:“非常高的幅度”有多高？您应该只能在这些引脚上看到 0V 或 3.3V，或者在引脚由于某种原因未打开(或关闭)的情况下处于 float 状态。