fcd.c

/***************************************************************************
 *  This file is part of Qthid.
 * 
 *  Copyright (C) 2010  Howard Long, G6LVB
 *  CopyRight (C) 2011  Alexandru Csete, OZ9AEC
 *                      Mario Lorenz, DL5MLO
 * 
 *  Qthid is free software: you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation, either version 3 of the License, or
 *  (at your option) any later version.
 *
 *  Qthid is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with Qthid.  If not, see <http://www.gnu.org/licenses/>.
 *
 ***************************************************************************/

#define FCD
#include <string.h>
#ifdef WIN32
    #include <malloc.h>
#else
    #include <stdlib.h>
#endif
#include "hidapi.h"
#include "fcd.h"
#include "fcdhidcmd.h"
#include <stdio.h>


#define FALSE 0
#define TRUE 1
typedef int BOOL;


const unsigned short _usVID=0x04D8;  /*!< USB vendor ID. */
const unsigned short _usPID=0xFB56;  /*!< USB product ID. */



/** \brief Open FCD device.
  * \return Pointer to the FCD HID device or NULL if none found
  *
  * This function looks for FCD devices connected to the computer and
  * opens the first one found.
  */
static hid_device *fcdOpen(void)
{
    struct hid_device_info *phdi=NULL;
    hid_device *phd=NULL;
    char *pszPath=NULL;

    phdi=hid_enumerate(_usVID,_usPID);
    if (phdi==NULL)
    {
        return NULL; // No FCD device found
    }

    pszPath=strdup(phdi->path);
    if (pszPath==NULL)
    {
        return NULL;
    }

    hid_free_enumeration(phdi);
    phdi=NULL;

    if ((phd=hid_open_path(pszPath)) == NULL)
    {
        free(pszPath);
        pszPath=NULL;

        return NULL;
    }

    free(pszPath);
    pszPath=NULL;

    return phd;
}


/** \brief Close FCD HID device. */
static void fcdClose(hid_device *phd)
{
    hid_close(phd);
}


/** \brief Get FCD mode.
  * \return The current FCD mode.
  * \sa FCD_MODE_ENUM
  */
EXTERN FCD_API_EXPORT FCD_API_CALL FCD_MODE_ENUM fcdGetMode(void)
{
    hid_device *phd=NULL;
    unsigned char aucBufIn[65];
    unsigned char aucBufOut[65];
    FCD_MODE_ENUM fcd_mode = FCD_MODE_NONE;


    phd = fcdOpen();

    if (phd == NULL)
    {
        return FCD_MODE_NONE;
    }

    /* Send a BL Query Command */
    aucBufOut[0] = 0; // Report ID, ignored
    aucBufOut[1] = FCD_CMD_BL_QUERY;
    hid_write(phd, aucBufOut, 65);
    memset(aucBufIn, 0xCC, 65); // Clear out the response buffer
    hid_read(phd, aucBufIn, 65);

    fcdClose(phd);
    phd = NULL;

    /* first check status bytes then check which mode */
    if (aucBufIn[0]==FCD_CMD_BL_QUERY && aucBufIn[1]==1) {

        /* In bootloader mode we have the string "FCDBL" starting at acBufIn[2] **/
        if (strncmp((char *)(aucBufIn+2), "FCDBL", 5) == 0) {
            fcd_mode = FCD_MODE_BL;
        }
        /* In application mode we have "FCDAPP_18.06" where the number is the FW version */
        else if (strncmp((char *)(aucBufIn+2), "FCDAPP", 6) == 0) {
            fcd_mode = FCD_MODE_APP;
        }
        /* either no FCD or firmware less than 18f */
        else {
            fcd_mode = FCD_MODE_NONE;
        }
    }

    return fcd_mode;
}


/** \brief Get FCD firmware version as string.
  * \param str The returned vesion number as a 0 terminated string (must be pre-allocated)
  * \return The current FCD mode.
  * \sa FCD_MODE_ENUM
  */
EXTERN FCD_API_EXPORT FCD_API_CALL FCD_MODE_ENUM fcdGetFwVerStr(char *str)
{
    hid_device *phd=NULL;
    unsigned char aucBufIn[65];
    unsigned char aucBufOut[65];
    FCD_MODE_ENUM fcd_mode = FCD_MODE_NONE;


    phd = fcdOpen();

    if (phd == NULL)
    {
        return FCD_MODE_NONE;
    }

    /* Send a BL Query Command */
    aucBufOut[0] = 0; // Report ID, ignored
    aucBufOut[1] = FCD_CMD_BL_QUERY;
    hid_write(phd, aucBufOut, 65);
    memset(aucBufIn, 0xCC, 65); // Clear out the response buffer
    hid_read(phd, aucBufIn, 65);

    fcdClose(phd);
    phd = NULL;

    /* first check status bytes then check which mode */
    if (aucBufIn[0]==FCD_CMD_BL_QUERY && aucBufIn[1]==1) {

        /* In bootloader mode we have the string "FCDBL" starting at acBufIn[2] **/
        if (strncmp((char *)(aucBufIn+2), "FCDBL", 5) == 0) {
            fcd_mode = FCD_MODE_BL;
        }
        /* In application mode we have "FCDAPP_18.06" where the number is the FW version */
        else if (strncmp((char *)(aucBufIn+2), "FCDAPP", 6) == 0) {
            strncpy(str, (char *)(aucBufIn+9), 5);
            str[5] = 0;
            fcd_mode = FCD_MODE_APP;
        }
        /* either no FCD or firmware less than 18f */
        else {
            fcd_mode = FCD_MODE_NONE;
        }
    }

    return fcd_mode;
}


/** \brief Get hardware and firmware dependent FCD capabilities.
  * \param fcd_caps Pointer to an FCD_CAPS_STRUCT
  * \return The current FCD mode.
  *
  * This function queries the FCD and extracts the hardware and firmware dependent
  * capabilities. Currently these capabilities are:
  *  - Bias T (available since S/N TBD)
  *  - Cellular block (the certified version of the FCD)
  * When the FCD is in application mode, the string returned by the query command is
  * (starting at index 2):
  *    FCDAPP 18.08 Brd 1.0 No blk
  * 1.0 means no bias tee, 1.1 means there is a bias tee
  * 'No blk' means it is not cellular blocked.
  *
  * Ref: http://uk.groups.yahoo.com/group/FCDevelopment/message/303
  */
EXTERN FCD_API_EXPORT FCD_API_CALL FCD_MODE_ENUM fcdGetCaps(FCD_CAPS_STRUCT *fcd_caps)
{
    hid_device *phd=NULL;
    unsigned char aucBufIn[65];
    unsigned char aucBufOut[65];
    FCD_MODE_ENUM fcd_mode = FCD_MODE_NONE;

    /* clear output buffer */
    fcd_caps->hasBiasT = 0;
    fcd_caps->hasCellBlock = 0;

    phd = fcdOpen();

    if (phd == NULL)
    {
        return FCD_MODE_NONE;
    }

    /* Send a BL Query Command */
    aucBufOut[0] = 0; // Report ID, ignored
    aucBufOut[1] = FCD_CMD_BL_QUERY;
    hid_write(phd, aucBufOut, 65);
    memset(aucBufIn, 0xCC, 65); // Clear out the response buffer
    hid_read(phd, aucBufIn, 65);

    fcdClose(phd);
    phd = NULL;

    /* first check status bytes then check which mode */
    if (aucBufIn[0]==FCD_CMD_BL_QUERY && aucBufIn[1]==1) {

        /* In bootloader mode we have the string "FCDBL" starting at acBufIn[2] **/
        if (strncmp((char *)(aucBufIn+2), "FCDBL", 5) == 0) {
            fcd_mode = FCD_MODE_BL;
        }
        /* In application mode we have "FCDAPP 18.08 Brd 1.0 No blk" (see API doc) */
        else if (strncmp((char *)(aucBufIn+2), "FCDAPP", 6) == 0) {

            /* Bias T */
            fcd_caps->hasBiasT = (aucBufIn[21] == '1') ? 1 : 0;

            /* cellular block */
            if (strncmp((char *)(aucBufIn+23), "No blk", 6) == 0) {
                fcd_caps->hasCellBlock = 0;
            } else {
                fcd_caps->hasCellBlock = 1;
            }

            fcd_mode = FCD_MODE_APP;
        }
        /* either no FCD or firmware less than 18f */
        else {
            fcd_mode = FCD_MODE_NONE;
        }
    }

    return fcd_mode;
}


/** \brief Get hardware and firmware dependent FCD capabilities as string.
  * \param caps_str Pointer to a pre-allocated string buffer where the info will be copied.
  * \return The current FCD mode.
  *
  * This function queries the FCD and copies the returned string into the caps_str parameter.
  * THe return buffer must be at least 28 characters.
  * When the FCD is in application mode, the string returned by the query command is
  * (starting at index 2):
  *    FCDAPP 18.08 Brd 1.0 No blk
  * 1.0 means no bias tee, 1.1 means there is a bias tee
  * 'No blk' means it is not cellular blocked.
  *
  * Ref: http://uk.groups.yahoo.com/group/FCDevelopment/message/303
  */
EXTERN FCD_API_EXPORT FCD_API_CALL FCD_MODE_ENUM fcdGetCapsStr(char *caps_str)
{
    hid_device *phd=NULL;
    unsigned char aucBufIn[65];
    unsigned char aucBufOut[65];
    FCD_MODE_ENUM fcd_mode = FCD_MODE_NONE;


    phd = fcdOpen();

    if (phd == NULL)
    {
        return FCD_MODE_NONE;
    }

    /* Send a BL Query Command */
    aucBufOut[0] = 0; // Report ID, ignored
    aucBufOut[1] = FCD_CMD_BL_QUERY;
    hid_write(phd, aucBufOut, 65);
    memset(aucBufIn, 0xCC, 65); // Clear out the response buffer
    hid_read(phd, aucBufIn, 65);

    fcdClose(phd);
    phd = NULL;

    /* first check status bytes then check which mode */
    if (aucBufIn[0]==FCD_CMD_BL_QUERY && aucBufIn[1]==1) {

        /* In bootloader mode we have the string "FCDBL" starting at acBufIn[2] **/
        if (strncmp((char *)(aucBufIn+2), "FCDBL", 5) == 0) {
            fcd_mode = FCD_MODE_BL;
        }
        /* In application mode we have "FCDAPP 18.08 Brd 1.0 No blk" (see API doc) */
        else if (strncmp((char *)(aucBufIn+2), "FCDAPP", 6) == 0) {

            strncpy(caps_str, (char *)(aucBufIn+2), 27);
            caps_str[27] = 0;

            fcd_mode = FCD_MODE_APP;
        }
        /* either no FCD or firmware less than 18f */
        else {
            fcd_mode = FCD_MODE_NONE;
        }
    }

    return fcd_mode;
}



/** \brief Reset FCD to bootloader mode.
  * \return FCD_MODE_NONE
  *
  * This function is used to switch the FCD into bootloader mode in which
  * various firmware operations can be performed.
  */
EXTERN FCD_API_EXPORT FCD_API_CALL FCD_MODE_ENUM fcdAppReset(void)
{
    hid_device *phd=NULL;
    //unsigned char aucBufIn[65];
    unsigned char aucBufOut[65];

    phd = fcdOpen();

    if (phd == NULL)
    {
        return FCD_MODE_NONE;
    }

    // Send an App reset command
    aucBufOut[0] = 0; // Report ID, ignored
    aucBufOut[1] = FCD_CMD_APP_RESET;
    hid_write(phd, aucBufOut, 65);

    /** FIXME: hid_read() will occasionally hang due to a pthread_cond_wait() never returning.
        It seems that the read_callback() in hid-libusb.c will never receive any
        data during the reconfiguration. Since the same logic works in the native
        windows application, it could be a libusb thing. Anyhow, since the value
        returned by this function is not used, we may as well just skip the hid_read()
        and return FME_NONE.
        Correct switch from APP to BL mode can be observed in /var/log/messages (linux)
        (when in bootloader mode the device version includes 'BL')
    */
    /*
    memset(aucBufIn,0xCC,65); // Clear out the response buffer
    hid_read(phd,aucBufIn,65);

    if (aucBufIn[0]==FCDCMDAPPRESET && aucBufIn[1]==1)
    {
        FCDClose(phd);
        phd=NULL;
        return FME_APP;
    }
    FCDClose(phd);
    phd=NULL;
    return FME_BL;
    */

    fcdClose(phd);
    phd = NULL;

    return FCD_MODE_NONE;

}


/** \brief Set FCD frequency with kHz resolution.
  * \param nFreq The new frequency in kHz.
  * \return The FCD mode.
  *
  * This function sets the frequency of the FCD with 1 kHz resolution. The parameter
  * nFreq must already contain any necessary frequency corrention.
  *
  * \sa fcdAppSetFreq
  */
EXTERN FCD_API_EXPORT FCD_API_CALL FCD_MODE_ENUM fcdAppSetFreqkHz(int nFreq)
{
    hid_device *phd=NULL;
    unsigned char aucBufIn[65];
    unsigned char aucBufOut[65];

    phd = fcdOpen();

    if (phd == NULL)
    {
        return FCD_MODE_NONE;
    }

    // Send an App reset command
    aucBufOut[0] = 0; // Report ID, ignored
    aucBufOut[1] = FCD_CMD_APP_SET_FREQ_KHZ;
    aucBufOut[2] = (unsigned char)nFreq;
    aucBufOut[3] = (unsigned char)(nFreq>>8);
    aucBufOut[4] = (unsigned char)(nFreq>>16);
    hid_write(phd, aucBufOut, 65);
    memset(aucBufIn, 0xCC, 65); // Clear out the response buffer
    hid_read(phd, aucBufIn, 65);

    if (aucBufIn[0]==FCD_CMD_APP_SET_FREQ_KHZ && aucBufIn[1]==1)
    {
        fcdClose(phd);
        phd = NULL;

        return FCD_MODE_APP;
    }

    fcdClose(phd);
    phd = NULL;

    return FCD_MODE_BL;
}


/** \brief Reset FCD to application mode.
  * \return FCD_MODE_NONE
  *
  * This function is used to switch the FCD from bootloader mode
  * into application mode.
  */
EXTERN FCD_API_EXPORT FCD_API_CALL FCD_MODE_ENUM fcdBlReset(void)
{
    hid_device *phd=NULL;
//    unsigned char aucBufIn[65];
    unsigned char aucBufOut[65];

    phd = fcdOpen();

    if (phd == NULL)
    {
        return FCD_MODE_NONE;
    }

    // Send an BL reset command
    aucBufOut[0] = 0; // Report ID, ignored
    aucBufOut[1] = FCD_CMD_BL_RESET;
    hid_write(phd, aucBufOut, 65);

    /** FIXME: hid_read() will hang due to a pthread_cond_wait() never returning.
        It seems that the read_callback() in hid-libusb.c will never receive any
        data during the reconfiguration. Since the same logic works in the native
        windows application, it could be a libusb thing. Anyhow, since the value
        returned by this function is not used, we may as well jsut skip the hid_read()
        and return FME_NONE.
        Correct switch from BL to APP mode can be observed in /var/log/messages (linux)
        (when in bootloader mode the device version includes 'BL')
    */
    /*
    memset(aucBufIn,0xCC,65); // Clear out the response buffer
    hid_read(phd,aucBufIn,65);

    if (aucBufIn[0]==FCDCMDBLRESET && aucBufIn[1]==1)
    {
        FCDClose(phd);
        phd=NULL;
        return FME_BL;
    }
    FCDClose(phd);
    phd=NULL;
    return FME_APP;
    */

    fcdClose(phd);
    phd = NULL;

    return FCD_MODE_NONE;

}


/** \brief Erase firmware from FCD.
  * \return The FCD mode
  *
  * This function deletes the firmware from the FCD. This is required
  * before writing new firmware into the FCD.
  *
  * \sa fcdBlWriteFirmware
  */
EXTERN FCD_API_EXPORT FCD_API_CALL FCD_MODE_ENUM fcdBlErase(void)
{
    hid_device *phd=NULL;
    unsigned char aucBufIn[65];
    unsigned char aucBufOut[65];

    phd = fcdOpen();

    if (phd == NULL)
    {
        return FCD_MODE_NONE;
    }

    // Send an App reset command
    aucBufOut[0] = 0; // Report ID, ignored
    aucBufOut[1] = FCD_CMD_BL_ERASE;
    hid_write(phd, aucBufOut, 65);
    memset(aucBufIn, 0xCC, 65); // Clear out the response buffer
    hid_read(phd, aucBufIn, 65);

    if (aucBufIn[0]==FCD_CMD_BL_ERASE && aucBufIn[1]==1)
    {
        fcdClose(phd);
        phd = NULL;

        return FCD_MODE_BL;
    }

    fcdClose(phd);
    phd = NULL;

    return FCD_MODE_APP;
}


/** \brief Write new firmware into the FCD.
  * \param pc Pointer to the new firmware data
  * \param n64size The number of bytes in the data
  * \return The FCD mode
  *
  * This function is used to upload new firmware into the FCD flash.
  *
  * \sa fcdBlErase
  */
EXTERN FCD_API_EXPORT FCD_API_CALL FCD_MODE_ENUM fcdBlWriteFirmware(char *pc, int64_t n64Size)
{
    hid_device *phd=NULL;
    unsigned char aucBufIn[65];
    unsigned char aucBufOut[65];
    uint32_t u32AddrStart;
    uint32_t u32AddrEnd;
    uint32_t u32Addr;
    BOOL bFinished=FALSE;

    phd = fcdOpen();

    if (phd==NULL)
    {
        return FCD_MODE_NONE;
    }

    // Get the valid flash address range
    aucBufOut[0] = 0; // Report ID, ignored
    aucBufOut[1] = FCD_CMD_BL_GET_BYTE_ADDR_RANGE;
    hid_write(phd, aucBufOut, 65);
    memset(aucBufIn, 0xCC, 65); // Clear out the response buffer
    hid_read(phd, aucBufIn, 65);

    if (aucBufIn[0]!=FCD_CMD_BL_GET_BYTE_ADDR_RANGE || aucBufIn[1]!=1)
    {
        fcdClose(phd);
        phd = NULL;

        return FCD_MODE_APP;
    }

    u32AddrStart=
        aucBufIn[2]+
        (((uint32_t)aucBufIn[3])<<8)+
        (((uint32_t)aucBufIn[4])<<16)+
        (((uint32_t)aucBufIn[5])<<24);
    u32AddrEnd=
        aucBufIn[6]+
        (((uint32_t)aucBufIn[7])<<8)+
        (((uint32_t)aucBufIn[8])<<16)+
        (((uint32_t)aucBufIn[9])<<24);

    // Set start address for flash
    aucBufOut[0] = 0; // Report ID, ignored
    aucBufOut[1] = FCD_CMD_BL_SET_BYTE_ADDR;
    aucBufOut[2] = ((unsigned char)u32AddrStart);
    aucBufOut[3] = ((unsigned char)(u32AddrStart>>8));
    aucBufOut[4] = ((unsigned char)(u32AddrStart>>16));
    aucBufOut[5] = ((unsigned char)(u32AddrStart>>24));
    hid_write(phd, aucBufOut, 65);
    memset(aucBufIn, 0xCC, 65); // Clear out the response buffer
    hid_read(phd, aucBufIn, 65);

    if (aucBufIn[0]!=FCD_CMD_BL_SET_BYTE_ADDR || aucBufIn[1]!=1)
    {
        fcdClose(phd);
        phd = NULL;

        return FCD_MODE_APP;
    }

    // Write blocks
    aucBufOut[0] = 0; // Report ID, ignored
    aucBufOut[1] = FCD_CMD_BL_WRITE_FLASH_BLOCK;
    for (u32Addr=u32AddrStart; u32Addr+47<u32AddrEnd && u32Addr+47<n64Size && !bFinished; u32Addr+=48)
    {
        memcpy(&aucBufOut[3], &pc[u32Addr], 48);

        hid_write(phd, aucBufOut, 65);
        memset(aucBufIn, 0xCC, 65); // Clear out the response buffer
        hid_read(phd, aucBufIn, 65);

        if (aucBufIn[0]!=FCD_CMD_BL_WRITE_FLASH_BLOCK || aucBufIn[1]!=1)
        {
            bFinished = TRUE;
            fcdClose(phd);
            phd = NULL;

            return FCD_MODE_APP;
        }
    }

    fcdClose(phd);
    phd = NULL;

    return FCD_MODE_BL;
}


/** \brief Verify firmware in FCd flash.
  * \param pc Pointer to firmware data to verify against.
  * \param n64Size Size of the data in pc.
  * \return The FCD_MODE_BL if verification was succesful.
  *
  * This function verifies the firmware currently in the FCd flash against the firmware
  * image pointed to by pc. The function return FCD_MODE_BL if the verification is OK and
  * FCD_MODE_APP otherwise.
  */
EXTERN FCD_API_EXPORT FCD_API_CALL FCD_MODE_ENUM fcdBlVerifyFirmware(char *pc, int64_t n64Size)
{
    hid_device *phd=NULL;
    unsigned char aucBufIn[65];
    unsigned char aucBufOut[65];
    uint32_t u32AddrStart;
    uint32_t u32AddrEnd;
    uint32_t u32Addr;
    BOOL bFinished=FALSE;

    phd = fcdOpen();

    if (phd==NULL)
    {
        return FCD_MODE_NONE;
    }

    // Get the valid flash address range
    aucBufOut[0] = 0; // Report ID, ignored
    aucBufOut[1] = FCD_CMD_BL_GET_BYTE_ADDR_RANGE;
    hid_write(phd, aucBufOut, 65);
    memset(aucBufIn, 0xCC, 65); // Clear out the response buffer
    hid_read(phd, aucBufIn, 65);

    if (aucBufIn[0]!=FCD_CMD_BL_GET_BYTE_ADDR_RANGE || aucBufIn[1]!=1)
    {
        fcdClose(phd);
        phd = NULL;

        return FCD_MODE_APP;
    }

    u32AddrStart=
        aucBufIn[2]+
        (((uint32_t)aucBufIn[3])<<8)+
        (((uint32_t)aucBufIn[4])<<16)+
        (((uint32_t)aucBufIn[5])<<24);

    u32AddrEnd=
        aucBufIn[6]+
        (((uint32_t)aucBufIn[7])<<8)+
        (((uint32_t)aucBufIn[8])<<16)+
        (((uint32_t)aucBufIn[9])<<24);

    // Set start address for flash
    aucBufOut[0] = 0; // Report ID, ignored
    aucBufOut[1] = FCD_CMD_BL_SET_BYTE_ADDR;
    aucBufOut[2] = ((unsigned char)u32AddrStart);
    aucBufOut[3] = ((unsigned char)(u32AddrStart>>8));
    aucBufOut[4] = ((unsigned char)(u32AddrStart>>16));
    aucBufOut[5] = ((unsigned char)(u32AddrStart>>24));
    hid_write(phd, aucBufOut, 65);
    memset(aucBufIn, 0xCC, 65); // Clear out the response buffer
    hid_read(phd, aucBufIn, 65);

    if (aucBufIn[0]!=FCD_CMD_BL_SET_BYTE_ADDR || aucBufIn[1]!=1)
    {
        fcdClose(phd);
        phd = NULL;

        return FCD_MODE_APP;
    }

    // Read blocks
    aucBufOut[0] = 0; // Report ID, ignored
    aucBufOut[1] = FCD_CMD_BL_READ_FLASH_BLOCK;
    for (u32Addr=u32AddrStart; u32Addr+47<u32AddrEnd && u32Addr+47<n64Size && !bFinished; u32Addr+=48)
    {
        hid_write(phd, aucBufOut, 65);
        memset(aucBufIn, 0xCC, 65); // Clear out the response buffer
        hid_read(phd, aucBufIn, 65);

        if (aucBufIn[0]!=FCD_CMD_BL_READ_FLASH_BLOCK || aucBufIn[1]!=1)
        {
            bFinished = TRUE;
            fcdClose(phd);
            phd = NULL;

            return FCD_MODE_APP;
        }

        if (memcmp(&aucBufIn[2],&pc[u32Addr],48)!=0)
        {
            bFinished = TRUE;
            fcdClose(phd);
            phd = NULL;

            return FCD_MODE_APP;
        }
    }

    fcdClose(phd);
    phd = NULL;

    return FCD_MODE_BL;
}



/** \brief Write FCD parameter (e.g. gain or filter)
  * \param u8Cmd The command byte / parameter ID, see FCD_CMD_APP_SET_*
  * \param pu8Data The parameter value to be written
  * \param u8len Length of pu8Data in bytes
  * \return One of FCD_MODE_NONE, FCD_MODE_APP or FCD_MODE_BL (see description)
  *
  * This function can be used to set the value of a parameter in the FCD for which there is no
  * high level API call. It gives access to the low level API of the FCD and the caller is expected
  * to be aware of the various FCD commands, since they are required to be supplied as parameter
  * to this function.
  *
  * The return value can be used to determine the success or failure of the command execution:
  * - FCD_MODE_APP : Reply from FCD was as expected (nominal case).
  * - FCD_MODE_BL : Reply from FCD was not as expected.
  * - FCD_MODE_NONE : No FCD was found
  */
EXTERN FCD_API_EXPORT FCD_API_CALL FCD_MODE_ENUM fcdAppSetParam(uint8_t u8Cmd, uint8_t *pu8Data, uint8_t u8len)
{
    hid_device *phd=NULL;
    unsigned char aucBufOut[65];
    unsigned char aucBufIn[65];


    phd = fcdOpen();

    if (phd == NULL)
    {
        return FCD_MODE_NONE;
    }

    aucBufOut[0]=0; // Report ID, ignored
    aucBufOut[1]=u8Cmd;
    memcpy(aucBufOut+2, pu8Data,u8len);
    hid_write(phd,aucBufOut,65);

    /* we must read after each write in order to empty FCD/HID buffer */
    memset(aucBufIn,0xCC,65); // Clear out the response buffer
    hid_read(phd,aucBufIn,65);

    /* Check the response, if OK return FCD_MODE_APP */
    if (aucBufIn[0]==u8Cmd && aucBufIn[1]==1) {
        fcdClose(phd);
        phd = NULL;

        return FCD_MODE_APP;
    }

    /* Response did not contain the expected bytes */
    fcdClose(phd);
    phd = NULL;

    return FCD_MODE_BL;

}


/** \brief Read FCD parameter (e.g. gain or filter)
  * \param u8Cmd The command byte / parameter ID, see FCD_CMD_APP_GET_*
  * \param pu8Data TPointer to buffer where the parameter value(s) will be written
  * \param u8len Length of pu8Data in bytes
  * \return One of FCD_MODE_NONE, FCD_MODE_APP or FCD_MODE_BL (see description)
  *
  * This function can be used to read the value of a parameter in the FCD for which there is no
  * high level API call. It gives access to the low level API of the FCD and the caller is expected
  * to be aware of the various FCD commands, since they are required to be supplied as parameter
  * to this function.
  *
  * The return value can be used to determine the success or failure of the command execution:
  * - FCD_MODE_APP : Reply from FCD was as expected (nominal case).
  * - FCD_MODE_BL : Reply from FCD was not as expected.
  * - FCD_MODE_NONE : No FCD was found
  */
EXTERN FCD_API_EXPORT FCD_API_CALL FCD_MODE_ENUM fcdAppGetParam(uint8_t u8Cmd, uint8_t *pu8Data, uint8_t u8len)
{
    hid_device *phd=NULL;
    unsigned char aucBufOut[65];
    unsigned char aucBufIn[65];

    phd = fcdOpen();
    if (phd == NULL)
    {
        return FCD_MODE_NONE;
    }

    aucBufOut[0]=0; // Report ID, ignored
    aucBufOut[1]=u8Cmd;
    hid_write(phd,aucBufOut,65);

    memset(aucBufIn,0xCC,65); // Clear out the response buffer
    hid_read(phd,aucBufIn,65);
    /* Copy return data to output buffer (even if cmd exec failed) */
    memcpy(pu8Data,aucBufIn+2,u8len);

    /* Check status bytes in returned data */
    if (aucBufIn[0]==u8Cmd && aucBufIn[1]==1) {
        fcdClose(phd);
        phd = NULL;

        return FCD_MODE_APP;
    }

    /* Response did not contain the expected bytes */
    fcdClose(phd);
    phd = NULL;

    return FCD_MODE_BL;
}