/**
* @file IAP_YMODEM_ATY.c
*
* @param Project DEVICE_GENERAL_ATY_LIB
*
* @author ATY
*
* @copyright
*       - Copyright 2017 - 2023 MZ-ATY
*       - This code follows:
*           - MZ-ATY Various Contents Joint Statement -
*               <a href="https://mengze.top/MZ-ATY_VCJS">
*                        https://mengze.top/MZ-ATY_VCJS</a>
*           - CC 4.0 BY-NC-SA -
*               <a href="https://creativecommons.org/licenses/by-nc-sa/4.0/">
*                        https://creativecommons.org/licenses/by-nc-sa/4.0/</a>
*       - Your use will be deemed to have accepted the terms of this statement.
*
* @brief Familiar functions of IAP with YMODEM for all embedded device
*
* @version
*       - 1_01_240911 > ATY
*           -# Preliminary version, first Release
*       - 1_01_250701 > ATY
*           -# real fix to lib type
*       - 1_01_250704 > ATY
*           -# finish uart and ucdc IAP whole test
********************************************************************************
*/

#ifndef __IAP_YMODEM_ATY_C
#define __IAP_YMODEM_ATY_C

#include "IAP_YMODEM_ATY.h"

/******************************* For user *************************************/
uint8_t EmptyBuf[1] = {0};

#ifdef IAP_YMODEM_ATY_USB
USBD_CDC_HandleTypeDef* hcdc;
uint32_t ucdcRcvLength = 0;
uint8_t ucdcRcvOverFlag = 1;
uint32_t ucdcRcvLastTime = 0;
uint8_t ucdcRcvBuffer[APP_RX_DATA_SIZE] = {0};
#endif

void All_Reset(void)
{
    // Disable global interrupts
    __disable_irq();

    // Deinnit peripherals
    HAL_UART_DeInit(&Interface_UART);
    __HAL_RCC_USB_CLK_DISABLE();
    HAL_RCC_DeInit();
    HAL_DeInit();

    // Disable and reset SysTick timer
    SysTick->CTRL = 0;
    SysTick->LOAD = 0;
    SysTick->VAL = 0;

    // Optional: Disable and clear all NVIC interrupts
    for(int i = 0; i < 8; i++) {
        NVIC->ICER[i] = 0xFFFFFFFF;  // Disable all interrupts
        NVIC->ICPR[i] = 0xFFFFFFFF;  // Clear pending status
    }

    // Optional: Reset interrupt priority registers
    // for(int i = 0; i < 48; i++) {
    //     NVIC->IP[i] = 0;  // Set all priorities to default
    // }

    // Optional: Set vector table offset to App's address
    SCB->VTOR = APPLICATION_ADDRESS & 0x1FFFFF80;
}

void JumpToAppWithReset(void)
{
    All_Reset();
    JumpToApp(APPLICATION_ADDRESS);
}

void Interface_Clean(void)
{
#ifndef IAP_YMODEM_ATY_USB
#warning "NOT IAP_YMODEM_ATY_USB"
    __HAL_UART_FLUSH_DRREGISTER(&Interface_UART);
#else
#warning "IAP_YMODEM_ATY_USB"
    ucdcRcvLength = 0;
    ucdcRcvOverFlag = 1;

#endif
}

#ifdef IAP_YMODEM_ATY_USB
void PUT_IN_CDC_Receive_FS(uint8_t* Buf, uint32_t* Len)
{
    if(ucdcRcvOverFlag == 1){ // new start
        ucdcRcvOverFlag = 0;
        ucdcRcvLength = *Len;
        memcpy(ucdcRcvBuffer, Buf, *Len);
        if(*Len < 64){
            ucdcRcvOverFlag = 1;
        }
        else{
            ucdcRcvLastTime = HAL_GetTick();
        }
    }
    else{ // pending to before
        memcpy(ucdcRcvBuffer + ucdcRcvLength, Buf, *Len);
        ucdcRcvLength += *Len;
        if(*Len < 64){
            ucdcRcvOverFlag = 1;
        }
        else{
            ucdcRcvLastTime = HAL_GetTick();
        }
    }
    // USBD_CDC_SetRxBuffer(&hUsbDeviceFS, &Buf[0]);
    // USBD_CDC_ReceivePacket(&hUsbDeviceFS);
    // return (USBD_OK);
}
#endif

uint32_t timeoutCount = 0;
uint32_t timeoutFinal = 100;
HAL_StatusTypeDef Interface_Receive(uint8_t* bytes, uint16_t size, uint32_t timeout)
{
#ifndef IAP_YMODEM_ATY_USB
    HAL_StatusTypeDef state = HAL_UART_Receive(&Interface_UART, bytes, size, timeout);
    return state;
    // return HAL_UART_Receive(&Interface_UART, bytes, size, timeout);
#else
    hcdc = (USBD_CDC_HandleTypeDef*)hUsbDeviceFS.pClassData;
    if(hcdc->RxLength > APP_RX_DATA_SIZE)
        return HAL_ERROR;

    timeoutCount = 0;
    timeoutFinal = timeout;
    while(ucdcRcvLength == 0){
        timeoutCount++;
        if(timeoutCount > timeoutFinal){
            timeoutCount = 0;
            USBD_CDC_ReceivePacket(&hUsbDeviceFS);
            return HAL_TIMEOUT;
        }
        HAL_Delay(1);
    }
    if(ucdcRcvOverFlag == 0)
    {
        while(HAL_GetTick() - ucdcRcvLastTime < 200)
        {
        }
        ucdcRcvOverFlag = 1;
    }

    if(ucdcRcvLength > 0 && ucdcRcvLength <= APP_RX_DATA_SIZE){
        uint16_t copySize = (ucdcRcvLength > size) ? size : ucdcRcvLength;
        memcpy(bytes, ucdcRcvBuffer, copySize);
        ucdcRcvLength -= copySize;
        memcpy(ucdcRcvBuffer, ucdcRcvBuffer + copySize, ucdcRcvLength);
    }
    return HAL_OK;
#endif
}

HAL_StatusTypeDef Interface_Transmit(uint8_t* bytes, uint16_t size, uint32_t timeout)
{
#ifndef IAP_YMODEM_ATY_USB
    /* May be timeouted... */
    if(Interface_UART.gState == HAL_UART_STATE_TIMEOUT)
    {
        Interface_UART.gState = HAL_UART_STATE_READY;
    }
    return HAL_UART_Transmit(&Interface_UART, bytes, size, timeout);
#else
    Interface_Clean();
    ucdcRcvOverFlag = 1;
    timeoutCount = 0;
    timeoutFinal = timeout;
    while(CDC_Transmit_FS(bytes, size) != HAL_OK){
        timeoutCount++;
        if(timeoutCount > timeoutFinal)
            return HAL_TIMEOUT;
        HAL_Delay(1);
    }
    return HAL_OK;
#endif
}


/**
  * @brief  Display the Main Menu on HyperTerminal
  */
void Main_Menu(void)
{
    uint8_t key = 0;
    uint16_t errTimes = 0;
    uint32_t FlashProtection = 0;

    /* Initialise Flash */
    FLASH_If_Init();

    /* Test if any sector of Flash memory where user application will be loaded is write protected */
    FlashProtection = FLASH_If_GetWriteProtectionStatus();

    Interface_PutString("\r\n\r\n=================== Main Menu ============================\r\n\r\n");
    Interface_PutString("  Download image to the internal Flash ----------------- 1\r\n\r\n");
    Interface_PutString("  Upload image from the internal Flash ----------------- 2\r\n\r\n");
    Interface_PutString("  Execute the loaded application ----------------------- 3\r\n\r\n");

    if(FlashProtection != FLASHIF_PROTECTION_NONE)
    {
        Interface_PutString("  Disable the write protection ------------------------- 4\r\n\r\n");
    }
    else
    {
        Interface_PutString("  Enable the write protection -------------------------- 4\r\n\r\n");
    }
    Interface_PutString("==========================================================\r\n\r\n");

    while(1)
    {
        /* Clean the input path */
        Interface_Clean();

        /* Receive key */
        Interface_Receive(&key, 1, IAP_3_TIME);
        /* Auto jump to app */
        if(key == 0)
            key = 51;

        switch(key)
        {
            case '*':
                /* Upload user application from the Flash */
                Interface_Upload();
                break;
            case '2':
                /* Upload user application from the Flash */
                Interface_PutString("\r\nAuthorize wrong!\r\n\r\n");
                break;
            case '1':
                /* Download user application in the Flash */
                if(Interface_Download() != COM_OK)
                    break;
            case '3':
                Interface_PutString("\r\nStart program execution...\r\n");
                JumpToAppWithReset();
                break;
            case '4':
                if(FlashProtection != FLASHIF_PROTECTION_NONE)
                {
                    /* Disable the write protection */
                    if(FLASH_If_WriteProtectionConfig(FLASHIF_WRP_DISABLE) == FLASHIF_OK)
                    {
                        Interface_PutString("Write protection disabled...\r\n");
                        Interface_PutString("System will now restart...\r\n");
                        /* Launch the option byte loading */
                        HAL_FLASH_OB_Launch();
                    }
                    else
                    {
                        Interface_PutString("Error: Flash write un-protection failed...\r\n");
                    }
                }
                else
                {
                    if(FLASH_If_WriteProtectionConfig(FLASHIF_WRP_ENABLE) == FLASHIF_OK)
                    {
                        Interface_PutString("Write protection enabled...\r\n");
                        Interface_PutString("System will now restart...\r\n");
                        /* Launch the option byte loading */
                        HAL_FLASH_OB_Launch();
                    }
                    else
                    {
                        Interface_PutString("Error: Flash write protection failed...\r\n");
                    }
                }
                break;
            default:
                errTimes++;
                if(errTimes > 500){
                    Interface_PutString("Start program execution for max err...\r\n\r\n");
                    JumpToAppWithReset();
                }
                // Interface_PutString("Invalid Number ! ==> The number should be either 1, 2, 3 or 4\r\n");
                break;
        }
        key = 0;
    }
}

#include "rtc.h"
void Main_Cycle(void)
{
    uint8_t sKey[2] = {0};
    HAL_RTCEx_BKUPWrite(&hrtc, RTC_BKP_DR1, 101);
    HAL_RTCEx_BKUPWrite(&hrtc, RTC_BKP_DR2, 250);
    HAL_RTCEx_BKUPWrite(&hrtc, RTC_BKP_DR3, 705);
    Interface_PutString("\r\n\r\nS to start\r\n\r\n");
    while(1)
    {
        #ifdef IAP_YMODEM_ATY_USB
        if(hcdc->RxLength > 1024){
            uint8_t t[1] = {0};
            Interface_Receive(t, 1, 10);
            continue;
        }
        #endif
        if(1)
        {
            if(Interface_Receive(sKey, 2, IAP_S_TIME) == HAL_OK)
            {
                if(sKey[0] == 'S')
                {
                    uint8_t verStr[] = "BLA_V_1_01_250705\r\n";
                    Interface_Transmit(verStr, sizeof(verStr), 100);
                    if(sKey[1] == '3'){
                        Interface_Clean();
                        Interface_PutString("\r\nStart program execution...\r\n");
                        JumpToAppWithReset();
                    }
                   
                    else if(sKey[1] == '1'){
                        Interface_Clean();
                        if(Interface_Download() != COM_OK){
                            Interface_PutString("\r\nStart program execution...\r\n");
                            JumpToAppWithReset();
                        }
                    }
                    else{
                        Interface_Clean();
                        Main_Menu();
                    }
                }
                else{
                    Interface_Clean();
                }
            }
            else{
                Interface_Clean();
                Main_Menu();
            }
        }
        /* Keep the user application running */
        else
        {
            JumpToAppWithReset();
        }
    }
}

/* ****************************************************************************/


/* interface realize **********************************************************/
/**
  * @brief  Print a string on the HyperTerminal
  * @param  p_string: The string to be printed
  * @retval send state
  */
HAL_StatusTypeDef Interface_PutString(uint8_t* p_string)
{
#ifdef IAP_YMODEM_ATY_DBG
    uint16_t length = 0;
    while(p_string[length] != '\0')
    {
        length++;
    }
    return Interface_Transmit(p_string, length, TX_TIMEOUT);
#else
    return Interface_Transmit("", 0, TX_TIMEOUT);;
#endif
}

/**
  * @brief  Transmit a byte to the HyperTerminal
  * @param  bytes The byte to be sent
  * @retval send state
  */

HAL_StatusTypeDef Interface_PutByte(uint8_t bytes)
{
    return Interface_Transmit(&bytes, 1, TX_TIMEOUT);
}

/**
  * @brief  Download a file
  * @retval download state
  */
COM_StatusTypeDef Interface_Download(void)
{
    uint8_t number[11] = {0};
    uint32_t size = 0;
    COM_StatusTypeDef result;

    Interface_PutString("\r\nWaiting for the file to be sent... (press 'a' to abort)\r\n");
    result = Ymodem_Receive(&size);
    if(result == COM_OK)
    {
        Interface_PutString("\r\n\r\nProgramming Completed Successfully!\n\r--------------------------------\r\n Name: ");
        Interface_PutString(aFileName);
        Int2Str(number, size);
        Interface_PutString("\r\nSize: ");
        Interface_PutString(number);
        Interface_PutString(" Bytes\r\n");
        Interface_PutString("-------------------\r\n");
    }
    else if(result == COM_LIMIT)
    {
        Interface_PutString("\r\nThe image size is higher than the allowed space memory!\n\r");
    }
    else if(result == COM_DATA)
    {
        Interface_PutString("\r\nVerification failed!\n\r");
    }
    else if(result == COM_ABORT)
    {
        Interface_PutString("\r\nAborted by user.\n\r");
    }
    else
    {
        Interface_PutString("\r\nFailed to receive the file!\r\n");
    }
    return result;
}

/**
  * @brief  Upload a file
  */
void Interface_Upload(void)
{
    uint8_t status = 0;

    Interface_PutString("\r\n\r\nSelect receive file... (press 'a' to abort)\r\n");
    while(1)
    {
        Interface_Receive(&status, 1, RX_TIMEOUT);
        if(status == CRC16)
        {
            /* Transmit the flash image through ymodem protocol */
            status = Ymodem_Transmit((uint8_t*)APPLICATION_ADDRESS, (const uint8_t*)"UploadedFlashImage.bin", USER_FLASH_SIZE);

            if(status != 0)
            {
                if(status == COM_ABORT)
                    Interface_PutString("\r\nAborted by user.\n\r");
                else
                    Interface_PutString("\r\nError occurred while transmitting file\r\n");
            }
            else
            {
                Interface_PutString("\r\nFile uploaded successfully\r\n");
            }
            break;
        }
        else if(status == ABORT1 || status == ABORT2)
        {
            Interface_PutString("\r\nAborted by user.\n\r");
            break;
        }
    }
}


/* common *********************************************************************/
/**
  * @brief  Convert an Integer to a string
  * @param  p_str: The string output pointer
  * @param  intnum: The integer to be converted
  */
void Int2Str(uint8_t* p_str, uint32_t intnum)
{
    uint32_t i, divider = 1000000000, pos = 0, status = 0;

    for(i = 0; i < 10; i++)
    {
        p_str[pos++] = (intnum / divider) + 48;

        intnum = intnum % divider;
        divider /= 10;
        if((p_str[pos - 1] == '0') & (status == 0))
        {
            pos = 0;
        }
        else
        {
            status++;
        }
    }
}

/**
  * @brief  Convert a string to an integer
  * @param  p_inputstr: The string to be converted
  * @param  p_intnum: The integer value
  * @retval 1: Correct
  *         0: Error
  */
uint32_t Str2Int(uint8_t* p_inputstr, uint32_t* p_intnum)
{
    uint32_t i = 0, res = 0;
    uint32_t val = 0;

    if((p_inputstr[0] == '0') && ((p_inputstr[1] == 'x') || (p_inputstr[1] == 'X')))
    {
        i = 2;
        while((i < 11) && (p_inputstr[i] != '\0'))
        {
            if(ISVALIDHEX(p_inputstr[i]))
            {
                val = (val << 4) + CONVERTHEX(p_inputstr[i]);
            }
            else
            {
                /* Return 0, Invalid input */
                res = 0;
                break;
            }
            i++;
        }

        /* valid result */
        if(p_inputstr[i] == '\0')
        {
            *p_intnum = val;
            res = 1;
        }
    }
    else /* max 10-digit decimal input */
    {
        while((i < 11) && (res != 1))
        {
            if(p_inputstr[i] == '\0')
            {
                *p_intnum = val;
                /* return 1 correct */
                res = 1;
            }
            else if(((p_inputstr[i] == 'k') || (p_inputstr[i] == 'K')) && (i > 0))
            {
                val = val << 10;
                *p_intnum = val;
                res = 1;
            }
            else if(((p_inputstr[i] == 'm') || (p_inputstr[i] == 'M')) && (i > 0))
            {
                val = val << 20;
                *p_intnum = val;
                res = 1;
            }
            else if(ISVALIDDEC(p_inputstr[i]))
            {
                val = val * 10 + CONVERTDEC(p_inputstr[i]);
            }
            else
            {
                /* return 0, Invalid input */
                res = 0;
                break;
            }
            i++;
        }
    }

    return res;
}


/* flash_if *******************************************************************/
/**
  * @brief  Unlocks Flash for write access
  */
void FLASH_If_Init(void)
{
    /* Unlock the Program memory */
    HAL_FLASH_Unlock();

    /* Clear all FLASH flags */
    __HAL_FLASH_CLEAR_FLAG(FLASH_FLAG_EOP | FLASH_FLAG_PGERR | FLASH_FLAG_WRPERR);
    /* Unlock the Program memory */
    HAL_FLASH_Lock();
}

/**
  * @brief  This function does an erase of all user flash area
  * @param  start: start of user flash area
  * @retval FLASHIF_OK : user flash area successfully erased
  *         FLASHIF_ERASEKO : error occurred
  */
uint32_t FLASH_If_Erase(uint32_t start)
{
    uint32_t NbrOfPages = 0;
    uint32_t PageError = 0;
    FLASH_EraseInitTypeDef pEraseInit;
    HAL_StatusTypeDef status = HAL_OK;

    /* Unlock the Flash to enable the flash control register access */
    HAL_FLASH_Unlock();

    /* Get the sector where start the user flash area */
    NbrOfPages = (USER_FLASH_END_ADDRESS - start) / FLASH_PAGE_SIZE;

    pEraseInit.TypeErase = FLASH_TYPEERASE_PAGES;
    pEraseInit.PageAddress = start;
    pEraseInit.Banks = FLASH_BANK_1;
    pEraseInit.NbPages = NbrOfPages;
    status = HAL_FLASHEx_Erase(&pEraseInit, &PageError);

    /* Lock the Flash to disable the flash control register access (recommended
       to protect the FLASH memory against possible unwanted operation) */
    HAL_FLASH_Lock();

    if(status != HAL_OK)
    {
        /* Error occurred while page erase */
        return FLASHIF_ERASEKO;
    }

    return FLASHIF_OK;
}

/**
  * @brief  This function writes a data buffer in flash (data are 32-bit aligned).
  * @note   After writing data buffer, the flash content is checked.
  * @param  destination: start address for target location
  * @param  p_source: pointer on buffer with data to write
  * @param  length: length of data buffer (unit is 32-bit word)
  * @retval uint32_t 0: Data successfully written to Flash memory
  *         1: Error occurred while writing data in Flash memory
  *         2: Written Data in flash memory is different from expected one
  */
uint32_t FLASH_If_Write(uint32_t destination, uint32_t* p_source, uint32_t length)
{
    uint32_t i = 0;

    /* Unlock the Flash to enable the flash control register access */
    HAL_FLASH_Unlock();

    for(i = 0; (i < length) && (destination <= (USER_FLASH_END_ADDRESS - 4)); i++)
    {
        /* Device voltage range supposed to be [2.7V to 3.6V], the operation will
           be done by word */
        if(HAL_FLASH_Program(FLASH_TYPEPROGRAM_WORD, destination, *(uint32_t*)(p_source + i)) == HAL_OK)
        {
            /* Check the written value */
            if(*(uint32_t*)destination != *(uint32_t*)(p_source + i))
            {
                /* Flash content doesn't match SRAM content */
                return(FLASHIF_WRITINGCTRL_ERROR);
            }
            /* Increment FLASH destination address */
            destination += 4;
        }
        else
        {
            /* Error occurred while writing data in Flash memory */
            return (FLASHIF_WRITING_ERROR);
        }
    }

    /* Lock the Flash to disable the flash control register access (recommended
       to protect the FLASH memory against possible unwanted operation) */
    HAL_FLASH_Lock();

    return (FLASHIF_OK);
}

/**
  * @brief  Returns the write protection status of application flash area.
  * @retval If a sector in application area is write-protected returned value is a combinaison
            of the possible values : FLASHIF_PROTECTION_WRPENABLED, FLASHIF_PROTECTION_PCROPENABLED, ...
  *         If no sector is write-protected FLASHIF_PROTECTION_NONE is returned.
  */
uint32_t FLASH_If_GetWriteProtectionStatus(void)
{
    uint32_t ProtectedPAGE = FLASHIF_PROTECTION_NONE;
    FLASH_OBProgramInitTypeDef OptionsBytesStruct;

    /* Unlock the Flash to enable the flash control register access */
    HAL_FLASH_Unlock();

    /* Check if there are write protected sectors inside the user flash area */
    HAL_FLASHEx_OBGetConfig(&OptionsBytesStruct);

    /* Lock the Flash to disable the flash control register access (recommended
       to protect the FLASH memory against possible unwanted operation) */
    HAL_FLASH_Lock();

    /* Get pages already write protected */
    ProtectedPAGE = ~(OptionsBytesStruct.WRPPage) & FLASH_PAGE_TO_BE_PROTECTED;

    /* Check if desired pages are already write protected */
    if(ProtectedPAGE != 0)
    {
        /* Some sectors inside the user flash area are write protected */
        return FLASHIF_PROTECTION_WRPENABLED;
    }
    else
    {
        /* No write protected sectors inside the user flash area */
        return FLASHIF_PROTECTION_NONE;
    }
}

/**
  * @brief  Configure the write protection status of user flash area.
  * @param  protectionstate : FLASHIF_WRP_DISABLE or FLASHIF_WRP_ENABLE the protection
  * @retval uint32_t FLASHIF_OK if change is applied.
  */
uint32_t FLASH_If_WriteProtectionConfig(uint32_t protectionstate)
{
    uint32_t ProtectedPAGE = 0x0;
    FLASH_OBProgramInitTypeDef config_new, config_old;
    HAL_StatusTypeDef result = HAL_OK;


    /* Get pages write protection status */
    HAL_FLASHEx_OBGetConfig(&config_old);

    /* The parameter says whether we turn the protection on or off */
    config_new.WRPState = (protectionstate == FLASHIF_WRP_ENABLE ? OB_WRPSTATE_ENABLE : OB_WRPSTATE_DISABLE);

    /* We want to modify only the Write protection */
    config_new.OptionType = OPTIONBYTE_WRP;

    /* No read protection, keep BOR and reset settings */
    config_new.RDPLevel = OB_RDP_LEVEL_0;
    config_new.USERConfig = config_old.USERConfig;
    /* Get pages already write protected */
    ProtectedPAGE = config_old.WRPPage | FLASH_PAGE_TO_BE_PROTECTED;

    /* Unlock the Flash to enable the flash control register access */
    HAL_FLASH_Unlock();

    /* Unlock the Options Bytes */
    HAL_FLASH_OB_Unlock();

    /* Erase all the option Bytes */
    result = HAL_FLASHEx_OBErase();

    if(result == HAL_OK)
    {
        config_new.WRPPage = ProtectedPAGE;
        result = HAL_FLASHEx_OBProgram(&config_new);
    }

    return (result == HAL_OK ? FLASHIF_OK : FLASHIF_PROTECTION_ERRROR);
}


/* ymodem *********************************************************************/
/* activate the CRC16 integrity */
#define CRC16_F
/* ATTENTION - please keep this variable 32bit alligned */
uint8_t aPacketData[PACKET_1K_SIZE + PACKET_DATA_INDEX + PACKET_TRAILER_SIZE];
uint8_t aFileName[FILE_NAME_LENGTH];


/**
  * @brief  Receive a packet from sender
  * @param  data
  * @param  length
  *     0: end of transmission
  *     2: abort by sender
  *    >0: packet length
  * @param  timeout
  * @retval HAL_OK: normally return
  *         HAL_BUSY: abort by user
  */
static HAL_StatusTypeDef ReceivePacket(uint8_t* p_data, uint32_t* p_length, uint32_t timeout)
{
    uint32_t crc;
    uint32_t packet_size = 0;
    HAL_StatusTypeDef status;
    uint8_t byteOne;

    *p_length = 0;
    status = Interface_Receive(&byteOne, 1, timeout);

    if(status == HAL_OK)
    {
        switch(byteOne)
        {
            case SOH:
                packet_size = PACKET_SIZE;
                break;
            case STX:
                packet_size = PACKET_1K_SIZE;
                break;
            case EOT:
                break;
            case CA:
                if((Interface_Receive(&byteOne, 1, timeout) == HAL_OK) && (byteOne == CA))
                {
                    packet_size = 2;
                }
                else
                {
                    status = HAL_ERROR;
                }
                break;
            case ABORT1:
            case ABORT2:
                status = HAL_BUSY;
                break;
            default:
                status = HAL_ERROR;
                break;
        }
        *p_data = byteOne;

        if(packet_size >= PACKET_SIZE)
        {
            status = Interface_Receive(&p_data[PACKET_NUMBER_INDEX], packet_size + PACKET_OVERHEAD_SIZE, timeout);

            /* Simple packet sanity check */
            if(status == HAL_OK)
            {
                if(p_data[PACKET_NUMBER_INDEX] != ((p_data[PACKET_CNUMBER_INDEX]) ^ NEGATIVE_BYTE))
                {
                    packet_size = 0;
                    status = HAL_ERROR;
                }
                else
                {
                    /* Check packet CRC */
                    crc = p_data[packet_size + PACKET_DATA_INDEX] << 8;
                    crc += p_data[packet_size + PACKET_DATA_INDEX + 1];
                    if(Cal_CRC16(&p_data[PACKET_DATA_INDEX], packet_size) != crc)
                    {
                        packet_size = 0;
                        status = HAL_ERROR;
                    }
                }
            }
            else
            {
                packet_size = 0;
            }
        }
    }
    *p_length = packet_size;
    return status;
}

/**
  * @brief  Prepare the first block
  * @param  p_data:  output buffer
  * @param  p_file_name: name of the file to be sent
  * @param  length: length of the file to be sent in bytes
  */
static void PrepareIntialPacket(uint8_t* p_data, const uint8_t* p_file_name, uint32_t length)
{
    uint32_t i, j = 0;
    uint8_t astring[10];

    /* first 3 bytes are constant */
    p_data[PACKET_START_INDEX] = SOH;
    p_data[PACKET_NUMBER_INDEX] = 0x00;
    p_data[PACKET_CNUMBER_INDEX] = 0xff;

    /* Filename written */
    for(i = 0; (p_file_name[i] != '\0') && (i < FILE_NAME_LENGTH); i++)
    {
        p_data[i + PACKET_DATA_INDEX] = p_file_name[i];
    }

    p_data[i + PACKET_DATA_INDEX] = 0x00;

    /* file size written */
    Int2Str(astring, length);
    i = i + PACKET_DATA_INDEX + 1;
    while(astring[j] != '\0')
    {
        p_data[i++] = astring[j++];
    }

    /* padding with zeros */
    for(j = i; j < PACKET_SIZE + PACKET_DATA_INDEX; j++)
    {
        p_data[j] = 0;
    }
}

/**
  * @brief  Prepare the data packet
  * @param  p_source: pointer to the data to be sent
  * @param  p_packet: pointer to the output buffer
  * @param  pkt_nr: number of the packet
  * @param  size_blk: length of the block to be sent in bytes
  */
static void PreparePacket(uint8_t* p_source, uint8_t* p_packet, uint8_t pkt_nr, uint32_t size_blk)
{
    uint8_t* p_record;
    uint32_t i, size, packet_size;

    /* Make first three packet */
    packet_size = size_blk >= PACKET_1K_SIZE ? PACKET_1K_SIZE : PACKET_SIZE;
    size = size_blk < packet_size ? size_blk : packet_size;
    if(packet_size == PACKET_1K_SIZE)
    {
        p_packet[PACKET_START_INDEX] = STX;
    }
    else
    {
        p_packet[PACKET_START_INDEX] = SOH;
    }
    p_packet[PACKET_NUMBER_INDEX] = pkt_nr;
    p_packet[PACKET_CNUMBER_INDEX] = (~pkt_nr);
    p_record = p_source;

    /* Filename packet has valid data */
    for(i = PACKET_DATA_INDEX; i < size + PACKET_DATA_INDEX; i++)
    {
        p_packet[i] = *p_record++;
    }
    if(size <= packet_size)
    {
        for(i = size + PACKET_DATA_INDEX; i < packet_size + PACKET_DATA_INDEX; i++)
        {
            p_packet[i] = 0x1A; /* EOF (0x1A) or 0x00 */
        }
    }
}

/**
  * @brief  Update CRC16 for input byte
  * @param  crc_in input value
  * @param  input byte
  */
uint16_t UpdateCRC16(uint16_t crc_in, uint8_t byte)
{
    uint32_t crc = crc_in;
    uint32_t in = byte | 0x100;

    do
    {
        crc <<= 1;
        in <<= 1;
        if(in & 0x100)
            ++crc;
        if(crc & 0x10000)
            crc ^= 0x1021;
    }

    while(!(in & 0x10000));

    return crc & 0xffffu;
}

/**
  * @brief  Cal CRC16 for YModem Packet
  * @param  data
  * @param  length
  */
uint16_t Cal_CRC16(const uint8_t* p_data, uint32_t size)
{
    uint32_t crc = 0;
    const uint8_t* dataEnd = p_data + size;

    while(p_data < dataEnd)
        crc = UpdateCRC16(crc, *p_data++);

    crc = UpdateCRC16(crc, 0);
    crc = UpdateCRC16(crc, 0);

    return crc & 0xffffu;
}

/**
  * @brief  Calculate Check sum for YModem Packet
  * @param  p_data Pointer to input data
  * @param  size length of input data
  * @retval uint8_t checksum value
  */
uint8_t CalcChecksum(const uint8_t* p_data, uint32_t size)
{
    uint32_t sum = 0;
    const uint8_t* p_data_end = p_data + size;

    while(p_data < p_data_end)
    {
        sum += *p_data++;
    }

    return (sum & 0xffu);
}


/* Public functions ---------------------------------------------------------*/
/**
  * @brief  Receive a file using the ymodem protocol with CRC16.
  * @param  p_size The size of the file.
  * @retval COM_StatusTypeDef result of reception/programming
  */
COM_StatusTypeDef Ymodem_Receive(uint32_t* p_size)
{
    uint32_t i, packet_length, session_done = 0, file_done, errors = 0, session_begin = 0;
    uint32_t flashdestination, ramsource, filesize;
    uint8_t* file_ptr;
    uint8_t file_size[FILE_SIZE_LENGTH], tmp, packets_received;
    COM_StatusTypeDef result = COM_OK;

    /* Initialize flashdestination variable */
    flashdestination = APPLICATION_ADDRESS;

    while((session_done == 0) && (result == COM_OK))
    {
        packets_received = 0;
        file_done = 0;
        while((file_done == 0) && (result == COM_OK))
        {
            switch(ReceivePacket(aPacketData, &packet_length, DOWNLOAD_TIMEOUT))
            {
                case HAL_OK:
                    errors = 0;
                    switch(packet_length)
                    {
                        case 2:
                            /* Abort by sender */
                            Interface_PutByte(ACK);
                            result = COM_ABORT;
                            break;
                        case 0:
                            /* End of transmission */
                            Interface_PutByte(ACK);
                            file_done = 1;
                            break;
                        default:
                            /* Normal packet */
                            if(aPacketData[PACKET_NUMBER_INDEX] != packets_received)
                            {
                                Interface_PutByte(NAK);
                            }
                            else
                            {
                                if(packets_received == 0)
                                {
                                    /* File name packet */
                                    if(aPacketData[PACKET_DATA_INDEX] != 0)
                                    {
                                        /* File name extraction */
                                        i = 0;
                                        file_ptr = aPacketData + PACKET_DATA_INDEX;
                                        while((*file_ptr != 0) && (i < FILE_NAME_LENGTH))
                                        {
                                            aFileName[i++] = *file_ptr++;
                                        }

                                        /* File size extraction */
                                        aFileName[i++] = '\0';
                                        i = 0;
                                        file_ptr++;
                                        while((*file_ptr != ' ') && (i < FILE_SIZE_LENGTH))
                                        {
                                            file_size[i++] = *file_ptr++;
                                        }
                                        file_size[i++] = '\0';
                                        Str2Int(file_size, &filesize);

                                        /* Test the size of the image to be sent */
                                        /* Image size is greater than Flash size */
                                        if(*p_size > (USER_FLASH_SIZE + 1))
                                        {
                                            /* End session */
                                            tmp = CA;
                                            Interface_Transmit(&tmp, 1, NAK_TIMEOUT);
                                            Interface_Transmit(&tmp, 1, NAK_TIMEOUT);
                                            result = COM_LIMIT;
                                        }
                                        /* Erase user application area */
                                        FLASH_If_Erase(APPLICATION_ADDRESS);
                                        *p_size = filesize;

                                        Interface_PutByte(ACK);
                                        Interface_PutByte(CRC16);
                                    }
                                    /* File header packet is empty, end session */
                                    else
                                    {
                                        Interface_PutByte(ACK);
                                        file_done = 1;
                                        session_done = 1;
                                        break;
                                    }
                                }
                                else /* Data packet */
                                {
                                    ramsource = (uint32_t)&aPacketData[PACKET_DATA_INDEX];

                                    /* Write received data in Flash */
                                    if(FLASH_If_Write(flashdestination, (uint32_t*)ramsource, packet_length / 4) == FLASHIF_OK)
                                    {
                                        flashdestination += packet_length;
                                        Interface_PutByte(ACK);
                                    }
                                    else /* An error occurred while writing to Flash memory */
                                    {
                                        /* End session */
                                        Interface_PutByte(CA);
                                        Interface_PutByte(CA);
                                        result = COM_DATA;
                                    }
                                }
                                packets_received++;
                                session_begin = 1;
                            }
                            break;
                    }
                    break;
                case HAL_BUSY: /* Abort actually */
                    Interface_PutByte(CA);
                    Interface_PutByte(CA);
                    result = COM_ABORT;
                    break;
                default:
                    if(session_begin > 0)
                    {
                        errors++;
                    }
                    if(errors > MAX_ERRORS)
                    {
                        /* Abort communication */
                        Interface_PutByte(CA);
                        Interface_PutByte(CA);
                    }
                    else
                    {
                        /* Ask for a packet */
                        Interface_PutByte(CRC16);
                    }
                    break;
            }
        }
    }
    return result;
}

/**
  * @brief  Transmit a file using the ymodem protocol
  * @param  p_buf: Address of the first byte
  * @param  p_file_name: Name of the file sent
  * @param  file_size: Size of the transmission
  * @retval COM_StatusTypeDef result of the communication
  */
COM_StatusTypeDef Ymodem_Transmit(uint8_t* p_buf, const uint8_t* p_file_name, uint32_t file_size)
{
    uint32_t errors = 0, ack_recpt = 0, size = 0, pkt_size;
    uint8_t* p_buf_int;
    COM_StatusTypeDef result = COM_OK;
    uint32_t blk_number = 1;
    uint8_t a_rx_ctrl[2];
    uint8_t i;
#ifdef CRC16_F
    uint32_t temp_crc;
#else /* CRC16_F */
    uint8_t temp_chksum;
#endif /* CRC16_F */

    /* Prepare first block - header */
    PrepareIntialPacket(aPacketData, p_file_name, file_size);

    while((!ack_recpt) && (result == COM_OK))
    {
        /* Send Packet */
        Interface_Transmit(&aPacketData[PACKET_START_INDEX], PACKET_SIZE + PACKET_HEADER_SIZE, NAK_TIMEOUT);

        /* Send CRC or Check Sum based on CRC16_F */
#ifdef CRC16_F
        temp_crc = Cal_CRC16(&aPacketData[PACKET_DATA_INDEX], PACKET_SIZE);
        Interface_PutByte(temp_crc >> 8);
        Interface_PutByte(temp_crc & 0xFF);
#else /* CRC16_F */
        temp_chksum = CalcChecksum(&aPacketData[PACKET_DATA_INDEX], PACKET_SIZE);
        Interface_PutByte(temp_chksum);
#endif /* CRC16_F */

        /* Wait for Ack and 'C' */
        if(Interface_Receive(&a_rx_ctrl[0], 1, NAK_TIMEOUT) == HAL_OK)
        {
            if(a_rx_ctrl[0] == ACK)
            {
                ack_recpt = 1;
            }
            else if(a_rx_ctrl[0] == CA)
            {
                if((Interface_Receive(&a_rx_ctrl[0], 1, NAK_TIMEOUT) == HAL_OK) && (a_rx_ctrl[0] == CA))
                {
                    HAL_Delay(2);
                    Interface_Clean();
                    result = COM_ABORT;
                }
            }
            else if(a_rx_ctrl[0] == ABORT1 || a_rx_ctrl[0] == ABORT2)
            {
                result = COM_ABORT;
            }
        }
        else
        {
            errors++;
        }
        if(errors >= MAX_ERRORS)
        {
            result = COM_ERROR;
        }
    }

    p_buf_int = p_buf;
    size = file_size;

    /* Here 1024 bytes length is used to send the packets */
    while((size) && (result == COM_OK))
    {
        /* Prepare next packet */
        PreparePacket(p_buf_int, aPacketData, blk_number, size);
        ack_recpt = 0;
        a_rx_ctrl[0] = 0;
        errors = 0;

        /* Resend packet if NAK for few times else end of communication */
        while((!ack_recpt) && (result == COM_OK))
        {
            /* Send next packet */
            if(size >= PACKET_1K_SIZE)
            {
                pkt_size = PACKET_1K_SIZE;
            }
            else
            {
                pkt_size = PACKET_SIZE;
            }

            Interface_Transmit(&aPacketData[PACKET_START_INDEX], pkt_size + PACKET_HEADER_SIZE, NAK_TIMEOUT);

            /* Send CRC or Check Sum based on CRC16_F */
#ifdef CRC16_F
            temp_crc = Cal_CRC16(&aPacketData[PACKET_DATA_INDEX], pkt_size);
            Interface_PutByte(temp_crc >> 8);
            Interface_PutByte(temp_crc & 0xFF);
#else /* CRC16_F */
            temp_chksum = CalcChecksum(&aPacketData[PACKET_DATA_INDEX], pkt_size);
            Interface_PutByte(temp_chksum);
#endif /* CRC16_F */

            /* Wait for Ack */
            if((Interface_Receive(&a_rx_ctrl[0], 1, NAK_TIMEOUT) == HAL_OK) && (a_rx_ctrl[0] == ACK))
            {
                ack_recpt = 1;
                if(size > pkt_size)
                {
                    p_buf_int += pkt_size;
                    size -= pkt_size;
                    if(blk_number == (USER_FLASH_SIZE / PACKET_1K_SIZE))
                    {
                        result = COM_LIMIT; /* boundary error */
                    }
                    else
                    {
                        blk_number++;
                    }
                }
                else
                {
                    p_buf_int += pkt_size;
                    size = 0;
                }
            }
            else
            {
                errors++;
            }

            /* Resend packet if NAK  for a count of 10 else end of communication */
            if(errors >= MAX_ERRORS)
            {
                result = COM_ERROR;
            }
        }
    }

    /* Sending End Of Transmission char */
    ack_recpt = 0;
    a_rx_ctrl[0] = 0x00;
    errors = 0;
    while((!ack_recpt) && (result == COM_OK))
    {
        Interface_PutByte(EOT);

        /* Wait for Ack */
        if(Interface_Receive(&a_rx_ctrl[0], 1, NAK_TIMEOUT) == HAL_OK)
        {
            if(a_rx_ctrl[0] == ACK)
            {
                ack_recpt = 1;
            }
            else if(a_rx_ctrl[0] == CA)
            {
                if((Interface_Receive(&a_rx_ctrl[0], 1, NAK_TIMEOUT) == HAL_OK) && (a_rx_ctrl[0] == CA))
                {
                    HAL_Delay(2);
                    Interface_Clean();
                    result = COM_ABORT;
                }
            }
        }
        else
        {
            errors++;
        }

        if(errors >= MAX_ERRORS)
        {
            result = COM_ERROR;
        }
    }

    /* Empty packet sent - some terminal emulators need this to close session */
    if(result == COM_OK)
    {
        /* Preparing an empty packet */
        aPacketData[PACKET_START_INDEX] = SOH;
        aPacketData[PACKET_NUMBER_INDEX] = 0;
        aPacketData[PACKET_CNUMBER_INDEX] = 0xFF;
        for(i = PACKET_DATA_INDEX; i < (PACKET_SIZE + PACKET_DATA_INDEX); i++)
        {
            aPacketData[i] = 0x00;
        }

        /* Send Packet */
        Interface_Transmit(&aPacketData[PACKET_START_INDEX], PACKET_SIZE + PACKET_HEADER_SIZE, NAK_TIMEOUT);

        /* Send CRC or Check Sum based on CRC16_F */
#ifdef CRC16_F
        temp_crc = Cal_CRC16(&aPacketData[PACKET_DATA_INDEX], PACKET_SIZE);
        Interface_PutByte(temp_crc >> 8);
        Interface_PutByte(temp_crc & 0xFF);
#else /* CRC16_F */
        temp_chksum = CalcChecksum(&aPacketData[PACKET_DATA_INDEX], PACKET_SIZE);
        Interface_PutByte(temp_chksum);
#endif /* CRC16_F */

        /* Wait for Ack and 'C' */
        if(Interface_Receive(&a_rx_ctrl[0], 1, NAK_TIMEOUT) == HAL_OK)
        {
            if(a_rx_ctrl[0] == CA)
            {
                HAL_Delay(2);
                Interface_Clean();
                result = COM_ABORT;
            }
        }
    }

    return result; /* File transmitted successfully */
}







#endif /* __IAP_YMODEM_ATY_C */

/******************************** End Of File *********************************/