Revision 0:f71232252dcf, committed 2010-11-25

Comitter:

shintamainjp

Date:

Thu Nov 25 15:43:42 2010 +0000

Child:

1:43358d40f879

Commit message:

Initial version.

Changed in this revision

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/Camera_LS_Y201.cpp	Thu Nov 25 15:43:42 2010 +0000
@@ -0,0 +1,424 @@
+/**
+ * =============================================================================
+ * LS-Y201 device driver class (Version 0.0.1)
+ * Reference documents: LinkSprite JPEG Color Camera Serial UART Interface
+ *                      January 2010
+ * =============================================================================
+ * Copyright (c) 2010 Shinichiro Nakamura (CuBeatSystems)
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ * =============================================================================
+ */
+
+#include "Camera_LS_Y201.h"
+
+/**
+ * Create.
+ *
+ * @param tx Transmitter.
+ * @param rx Receiver.
+ */
+Camera_LS_Y201::Camera_LS_Y201(PinName tx, PinName rx) : serial(tx, rx) {
+    serial.baud(38400);
+}
+
+/**
+ * Dispose.
+ */
+Camera_LS_Y201::~Camera_LS_Y201() {
+}
+
+/**
+ * Reset module.
+ *
+ * @return Error code.
+ */
+Camera_LS_Y201::ErrorCode Camera_LS_Y201::reset() {
+    uint8_t send[4] = {
+        0x56,
+        0x00,
+        0x26,
+        0x00
+    };
+    uint8_t recv[4];
+
+    waitIdle();
+    if (!sendBytes(send, sizeof(send), 200 * 1000)) {
+        return SendError;
+    }
+    if (!recvBytes(recv, sizeof(recv), 200 * 1000)) {
+        return RecvError;
+    }
+    if ((recv[0] == 0x76)
+            && (recv[1] == 0x00)
+            && (recv[2] == 0x26)
+            && (recv[3] == 0x00)) {
+        ErrorCode r = waitInitEnd();
+        if (r != NoError) {
+            return r;
+        }
+        wait(4);
+        return NoError;
+    } else {
+        return UnexpectedReply;
+    }
+}
+
+/**
+ * Set image size.
+ *
+ * @param is Image size.
+ * @return Error code.
+ */
+Camera_LS_Y201::ErrorCode Camera_LS_Y201::setImageSize(ImageSize is) {
+    uint8_t send[9] = {
+        0x56,
+        0x00,
+        0x31,
+        0x05,
+        0x04,
+        0x01,
+        0x00,
+        0x19,
+        0x00    // 0x11:320x240, 0x00:640x480, 0x22:160x120
+    };
+    uint8_t recv[5];
+    switch (is) {
+        case ImageSize160x120:
+            send[8] = 0x22;
+            break;
+        case ImageSize320x280:
+            send[8] = 0x11;
+            break;
+        case ImageSize640x480:
+            send[8] = 0x00;
+            break;
+        default:
+            return InvalidArguments;
+    }
+    if (!sendBytes(send, sizeof(send), 200 * 1000)) {
+        return SendError;
+    }
+    if (!recvBytes(recv, sizeof(recv), 200 * 1000)) {
+        return RecvError;
+    }
+    if ((recv[0] == 0x76)
+            && (recv[1] == 0x00)
+            && (recv[2] == 0x31)
+            && (recv[3] == 0x00)
+            && (recv[4] == 0x00)) {
+        wait(1);
+        return reset();
+    } else {
+        return UnexpectedReply;
+    }
+}
+
+/**
+ * Take picture.
+ *
+ * @return Error code.
+ */
+Camera_LS_Y201::ErrorCode Camera_LS_Y201::takePicture() {
+    uint8_t send[5] = {
+        0x56,
+        0x00,
+        0x36,
+        0x01,
+        0x00
+    };
+    uint8_t recv[5];
+
+    if (!sendBytes(send, sizeof(send), 200 * 1000)) {
+        return SendError;
+    }
+    if (!recvBytes(recv, sizeof(recv), 200 * 1000)) {
+        return RecvError;
+    }
+
+    if ((recv[0] == 0x76)
+            && (recv[1] == 0x00)
+            && (recv[2] == 0x36)
+            && (recv[3] == 0x00)
+            && (recv[4] == 0x00)) {
+        return NoError;
+    } else {
+        return UnexpectedReply;
+    }
+}
+
+/**
+ * Read jpeg file size.
+ *
+ * @param fileSize File size.
+ * @return Error code.
+ */
+Camera_LS_Y201::ErrorCode Camera_LS_Y201::readJpegFileSize(int *fileSize) {
+    uint8_t send[5] = {
+        0x56,
+        0x00,
+        0x34,
+        0x01,
+        0x00
+    };
+    uint8_t recv[9];
+
+    if (!sendBytes(send, sizeof(send), 200 * 1000)) {
+        return SendError;
+    }
+    if (!recvBytes(recv, sizeof(recv), 200 * 1000)) {
+        return RecvError;
+    }
+
+    if ((recv[0] == 0x76)
+            && (recv[1] == 0x00)
+            && (recv[2] == 0x34)
+            && (recv[3] == 0x00)
+            && (recv[4] == 0x04)
+            && (recv[5] == 0x00)
+            && (recv[6] == 0x00)) {
+        *fileSize = ((recv[7] & 0x00ff) << 8)
+                    | ((recv[8] & 0x00ff) << 0);
+        return NoError;
+    } else {
+        return UnexpectedReply;
+    }
+}
+
+/**
+ * Read jpeg file content.
+ *
+ * @param func A pointer to a call back function.
+ * @return Error code.
+ */
+Camera_LS_Y201::ErrorCode Camera_LS_Y201::readJpegFileContent(void (*func)(uint8_t *buf, size_t siz)) {
+    uint8_t send[16] = {
+        0x56,
+        0x00,
+        0x32,
+        0x0C,
+        0x00,
+        0x0A,
+        0x00,
+        0x00,
+        0x00, // MH
+        0x00, // ML
+        0x00,
+        0x00,
+        0x00, // KH
+        0x00, // KL
+        0x00, // XX
+        0x00  // XX
+    };
+    uint8_t body[32];
+    uint16_t m = 0; // Staring address.
+    uint16_t k = sizeof(body); // Packet size.
+    uint16_t x = 10;    // Interval time. XX XX * 0.01m[sec]
+    bool end = false;
+    do {
+        send[8] = (m >> 8) & 0xff;
+        send[9] = (m >> 0) & 0xff;
+        send[12] = (k >> 8) & 0xff;
+        send[13] = (k >> 0) & 0xff;
+        send[14] = (x >> 8) & 0xff;
+        send[15] = (x >> 0) & 0xff;
+        /*
+         * Send a command.
+         */
+        if (!sendBytes(send, sizeof(send), 200 * 1000)) {
+            return SendError;
+        }
+        /*
+         * Read the header of the response.
+         */
+        uint8_t header[5];
+        if (!recvBytes(header, sizeof(header), 2 * 1000 * 1000)) {
+            return RecvError;
+        }
+        /*
+         * Check the response and fetch an image data.
+         */
+        if ((header[0] == 0x76)
+                && (header[1] == 0x00)
+                && (header[2] == 0x32)
+                && (header[3] == 0x00)
+                && (header[4] == 0x00)) {
+            if (!recvBytes(body, sizeof(body), 2 * 1000 * 1000)) {
+                return RecvError;
+            }
+            if (func != NULL) {
+                func(body, sizeof(body));
+            }
+            for (int i = 1; i < sizeof(body); i++) {
+                if ((body[i - 1] == 0xFF) && (body[i - 0] == 0xD9)) {
+                    end = true;
+                }
+            }
+        } else {
+            return UnexpectedReply;
+        }
+        /*
+         * Read the footer of the response.
+         */
+        uint8_t footer[5];
+        if (!recvBytes(footer, sizeof(footer), 2 * 1000 * 1000)) {
+            return RecvError;
+        }
+
+        m += sizeof(body);
+    } while (!end);
+    return NoError;
+}
+
+/**
+ * Stop taking pictures.
+ *
+ * @return Error code.
+ */
+Camera_LS_Y201::ErrorCode Camera_LS_Y201::stopTakingPictures() {
+    uint8_t send[5] = {
+        0x56,
+        0x00,
+        0x36,
+        0x01,
+        0x03
+    };
+    uint8_t recv[5];
+
+    if (!sendBytes(send, sizeof(send), 200 * 1000)) {
+        return SendError;
+    }
+    if (!recvBytes(recv, sizeof(recv), 200 * 1000)) {
+        return RecvError;
+    }
+
+    if ((recv[0] == 0x76)
+            && (recv[1] == 0x00)
+            && (recv[2] == 0x36)
+            && (recv[3] == 0x00)
+            && (recv[4] == 0x00)) {
+        return NoError;
+    } else {
+        return UnexpectedReply;
+    }
+}
+
+/**
+ * Wait init end codes.
+ *
+ * @return True if the data sended.
+ */
+Camera_LS_Y201::ErrorCode Camera_LS_Y201::waitInitEnd() {
+    static const char *PWR_ON_MSG = "Init end\x0d\x0a";
+    for (int i = 0; i < strlen(PWR_ON_MSG); i++) {
+        static const int MAXCNT = 128;
+        int cnt = 0;
+        uint8_t c = 0x00;
+        do {
+            if (!recvBytes(&c, sizeof(c), 500 * 1000)) {
+                return Timeout;
+            }
+
+            /*
+             * What is the version of the camera.
+             * You can check the version with this code.
+             *
+             * VC0703 1.00
+             * 3o ctrl in
+             * Init end
+             */
+#if 0
+            printf("%c", c);
+#endif
+
+            cnt++;
+            if (MAXCNT < cnt) {
+                return UnexpectedReply;
+            }
+        } while (c != PWR_ON_MSG[i]);
+    }
+    return NoError;
+}
+
+/**
+ * Send bytes to camera module.
+ *
+ * @param buf Pointer to the data buffer.
+ * @param len Length of the data buffer.
+ *
+ * @return True if the data sended.
+ */
+bool Camera_LS_Y201::sendBytes(uint8_t *buf, size_t len, int timeout_us) {
+    for (uint32_t i = 0; i < (uint32_t)len; i++) {
+        int cnt = 0;
+        while (!serial.writeable()) {
+            wait_us(1);
+            cnt++;
+            if (timeout_us < cnt) {
+                return false;
+            }
+        }
+        serial.putc(buf[i]);
+    }
+    return true;
+}
+
+/**
+ * Receive bytes from camera module.
+ *
+ * @param buf Pointer to the data buffer.
+ * @param len Length of the data buffer.
+ *
+ * @return True if the data received.
+ */
+bool Camera_LS_Y201::recvBytes(uint8_t *buf, size_t len, int timeout_us) {
+    for (uint32_t i = 0; i < (uint32_t)len; i++) {
+        int cnt = 0;
+        while (!serial.readable()) {
+            wait_us(1);
+            cnt++;
+            if (timeout_us < cnt) {
+                return false;
+            }
+        }
+        buf[i] = serial.getc();
+    }
+    return true;
+}
+
+/**
+ * Wait received.
+ *
+ * @return True if the data received.
+ */
+bool Camera_LS_Y201::waitRecv() {
+    while (!serial.readable()) {
+    }
+    return true;
+}
+
+/**
+ * Wait idle state.
+ */
+bool Camera_LS_Y201::waitIdle() {
+    while (serial.readable()) {
+        serial.getc();
+    }
+    return true;
+}

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/Camera_LS_Y201.h	Thu Nov 25 15:43:42 2010 +0000
@@ -0,0 +1,166 @@
+/**
+ * =============================================================================
+ * LS-Y201 device driver class (Version 0.0.1)
+ * Reference documents: LinkSprite JPEG Color Camera Serial UART Interface
+ *                      January 2010
+ * =============================================================================
+ * Copyright (c) 2010 Shinichiro Nakamura (CuBeatSystems)
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ * =============================================================================
+ */
+
+#ifndef LS_Y201_H
+#define LS_Y201_H
+
+#include "mbed.h"
+#include "SerialBuffered.h"
+
+/**
+ * Camera
+ */
+class Camera_LS_Y201 {
+public:
+
+    /**
+     * Create.
+     *
+     * @param tx Transmitter.
+     * @param rx Receiver.
+     */
+    Camera_LS_Y201(PinName tx, PinName rx);
+    
+    /**
+     * Dispose.
+     */
+    ~Camera_LS_Y201();
+    
+    /**
+     * Error code.
+     */
+    enum ErrorCode {
+        NoError = 0,
+        UnexpectedReply,
+        Timeout,
+        SendError,
+        RecvError,
+        InvalidArguments
+    };
+    
+    /**
+     * Image size.
+     */
+    enum ImageSize {
+        ImageSize160x120,   /**< 160x120. */
+        ImageSize320x280,   /**< 320x280. */
+        ImageSize640x480    /**< 640x480. */
+    };
+
+    /**
+     * Reset module.
+     *
+     * @return Error code.
+     */
+    ErrorCode reset();
+
+    /**
+     * Set image size.
+     *
+     * @param is Image size.
+     * @return Error code.
+     */
+    ErrorCode setImageSize(ImageSize is);
+
+    /**
+     * Take picture.
+     *
+     * @return Error code.
+     */
+    ErrorCode takePicture();
+
+    /**
+     * Read jpeg file size.
+     *
+     * @param fileSize File size.
+     * @return Error code.
+     */
+    ErrorCode readJpegFileSize(int *fileSize);
+
+    /**
+     * Read jpeg file content.
+     *
+     * @param func A pointer to a call back function.
+     * @return Error code.
+     */
+    ErrorCode readJpegFileContent(void (*func)(uint8_t *buf, size_t siz));
+
+    /**
+     * Stop taking pictures.
+     *
+     * @return Error code.
+     */
+    ErrorCode stopTakingPictures();
+
+private:
+    SerialBuffered serial;
+
+    /**
+     * Wait init end codes.
+     *
+     * @return Error code.
+     */
+    ErrorCode waitInitEnd();
+
+    /**
+     * Send bytes to camera module.
+     *
+     * @param buf Pointer to the data buffer.
+     * @param len Length of the data buffer.
+     *
+     * @return True if the data sended.
+     */
+    bool sendBytes(uint8_t *buf, size_t len, int timeout_us);
+
+    /**
+     * Receive bytes from camera module.
+     *
+     * @param buf Pointer to the data buffer.
+     * @param len Length of the data buffer.
+     *
+     * @return True if the data received.
+     */
+    bool recvBytes(uint8_t *buf, size_t len, int timeout_us);
+
+    /**
+     * Wait received.
+     *
+     * @return True if the data received.
+     */
+    bool waitRecv();
+
+    /**
+     * Wait idle state.
+     *
+     * @return True if it succeed.
+     */
+    bool waitIdle();
+
+};
+
+#endif

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/SerialBuffered.cpp	Thu Nov 25 15:43:42 2010 +0000
@@ -0,0 +1,127 @@
+/**
+ * =============================================================================
+ * LS-Y201 device driver class (Version 0.0.1)
+ * Reference documents: LinkSprite JPEG Color Camera Serial UART Interface
+ *                      January 2010
+ * =============================================================================
+ * Copyright (c) 2010 Shinichiro Nakamura (CuBeatSystems)
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ * 
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ * =============================================================================
+ */
+
+#include "mbed.h"
+#include "SerialBuffered.h"
+
+/**
+ * Create a buffered serial class.
+ *
+ * @param tx A pin for transmit.
+ * @param rx A pin for receive.
+ */
+SerialBuffered::SerialBuffered(PinName tx, PinName rx) : Serial(tx, rx) {
+    indexContentStart = 0;
+    indexContentEnd = 0;
+    timeout = 1;
+    attach(this, &SerialBuffered::handleInterrupt);
+}
+
+/**
+ * Destroy.
+ */
+SerialBuffered::~SerialBuffered() {
+}
+
+/**
+ * Set timeout for getc().
+ *
+ * @param ms milliseconds. (-1:Disable timeout)
+ */
+void SerialBuffered::setTimeout(int ms) {
+    timeout = ms;
+}
+
+/**
+ * Read requested bytes.
+ *
+ * @param bytes A pointer to a buffer.
+ * @param requested Length.
+ *
+ * @return Readed byte length.
+ */
+size_t SerialBuffered::readBytes(uint8_t *bytes, size_t requested) {
+    int i = 0;
+    while (i < requested) {
+        int c = getc();
+        if (c < 0) {
+            break;
+        }
+        bytes[i] = c;
+        i++;
+    }
+    return i;
+}
+
+/**
+ * Get a character.
+ *
+ * @return A character. (-1:timeout)
+ */
+int SerialBuffered::getc() {
+    timer.reset();
+    timer.start();
+    while (indexContentStart == indexContentEnd) {
+        wait_ms(1);
+        if ((timeout > 0) && (timer.read_ms() > timeout)) {
+            /*
+             * Timeout occured.
+             */
+            // printf("Timeout occured.\n");
+            return EOF;
+        }
+    }
+    timer.stop();
+
+    uint8_t result = buffer[indexContentStart++];
+    indexContentStart =  indexContentStart % BUFFERSIZE;
+
+    return result;
+}
+
+/**
+ * Returns 1 if there is a character available to read, 0 otherwise.
+ */
+int SerialBuffered::readable() {
+    return indexContentStart != indexContentEnd;
+}
+
+void SerialBuffered::handleInterrupt() {
+    while (Serial::readable()) {
+        if (indexContentStart == ((indexContentEnd + 1) % BUFFERSIZE)) {
+            /*
+             * Buffer overrun occured.
+             */
+            // printf("Buffer overrun occured.\n");
+            Serial::getc();
+        } else {
+            buffer[indexContentEnd++] = Serial::getc();
+            indexContentEnd = indexContentEnd % BUFFERSIZE;
+        }
+    }
+}

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/SerialBuffered.h	Thu Nov 25 15:43:42 2010 +0000
@@ -0,0 +1,89 @@
+/**
+ * =============================================================================
+ * LS-Y201 device driver class (Version 0.0.1)
+ * Reference documents: LinkSprite JPEG Color Camera Serial UART Interface
+ *                      January 2010
+ * =============================================================================
+ * Copyright (c) 2010 Shinichiro Nakamura (CuBeatSystems)
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ * 
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ * =============================================================================
+ */
+
+#ifndef _SERIAL_BUFFERED_H_
+#define _SERIAL_BUFFERED_H_
+
+/**
+ * Buffered serial class.
+ */
+class SerialBuffered : public Serial {
+public:
+    /**
+     * Create a buffered serial class.
+     *
+     * @param tx A pin for transmit.
+     * @param rx A pin for receive.
+     */
+    SerialBuffered(PinName tx, PinName rx);
+
+    /**
+     * Destroy.
+     */
+    virtual ~SerialBuffered();
+
+    /**
+     * Get a character.
+     *
+     * @return A character. (-1:timeout)
+     */
+    int getc();
+
+    /**
+     * Returns 1 if there is a character available to read, 0 otherwise.
+     */
+    int readable();
+
+    /**
+     * Set timeout for getc().
+     *
+     * @param ms milliseconds. (-1:Disable timeout)
+     */
+    void setTimeout(int ms);
+
+    /**
+     * Read requested bytes.
+     *
+     * @param bytes A pointer to a buffer.
+     * @param requested Length.
+     *
+     * @return Readed byte length.
+     */
+    size_t readBytes(uint8_t *bytes, size_t requested);
+
+private:
+    void handleInterrupt();
+    static const int BUFFERSIZE = 4096;
+    uint8_t buffer[BUFFERSIZE];            // points at a circular buffer, containing data from m_contentStart, for m_contentSize bytes, wrapping when you get to the end
+    uint16_t indexContentStart;   // index of first bytes of content
+    uint16_t indexContentEnd;     // index of bytes after last byte of content
+    int timeout;
+    Timer timer;
+};
+
+#endif