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

 *

 *             Microchip USB C18 Firmware -  CDC Version 1.0

 *

 *********************************************************************

 * FileName:        cdc.c

 * Dependencies:    See INCLUDES section below

 * Processor:       PIC18

 * Compiler:        C18 2.30.01+

 * Company:         Microchip Technology, Inc.

 *

 * Software License Agreement

 *

 * The software supplied herewith by Microchip Technology Incorporated

 * (the “Company”) for its PICmicro® Microcontroller is intended and

 * supplied to you, the Company’s customer, for use solely and

 * exclusively on Microchip PICmicro Microcontroller products. The

 * software is owned by the Company and/or its supplier, and is

 * protected under applicable copyright laws. All rights are reserved.

 * Any use in violation of the foregoing restrictions may subject the

 * user to criminal sanctions under applicable laws, as well as to

 * civil liability for the breach of the terms and conditions of this

 * license.

 *

 * THIS SOFTWARE IS PROVIDED IN AN “AS IS” CONDITION. NO WARRANTIES,

 * WHETHER EXPRESS, IMPLIED OR STATUTORY, INCLUDING, BUT NOT LIMITED

 * TO, IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A

 * PARTICULAR PURPOSE APPLY TO THIS SOFTWARE. THE COMPANY SHALL NOT,

 * IN ANY CIRCUMSTANCES, BE LIABLE FOR SPECIAL, INCIDENTAL OR

 * CONSEQUENTIAL DAMAGES, FOR ANY REASON WHATSOEVER.

 *

 * Author               Date        Comment

 *~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

 * Rawin Rojvanit       11/19/04    Original. RS-232 Emulation Subset

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

/** I N C L U D E S **********************************************************/

#include <p18cxxx.h>

#include "typedefs.h"

#include "usb.h"

#ifdef USB_USE_CDC

/** V A R I A B L E S ********************************************************/

#pragma udata

byte cdc_rx_len;            // total rx length

byte cdc_trf_state;         // States are defined cdc.h

POINTER pCDCSrc;            // Dedicated source pointer

POINTER pCDCDst;            // Dedicated destination pointer

byte cdc_tx_len;            // total tx length

byte cdc_mem_type;          // _ROM, _RAM

LINE_CODING line_coding;    // Buffer to store line coding information

CONTROL_SIGNAL_BITMAP control_signal_bitmap;

/*

 * SEND_ENCAPSULATED_COMMAND and GET_ENCAPSULATED_RESPONSE are required

 * requests according to the CDC specification.

 * However, it is not really being used here, therefore a dummy buffer is

 * used for conformance.

 */

#define dummy_length    0x08

byte dummy_encapsulated_cmd_response[dummy_length];

/** P R I V A T E  P R O T O T Y P E S ***************************************/

/** D E C L A R A T I O N S **************************************************/

#pragma code

/** C L A S S  S P E C I F I C  R E Q ****************************************/

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

 * Function:        void USBCheckCDCRequest(void)

 *

 * PreCondition:    None

 *

 * Input:           None

 *

 * Output:          None

 *

 * Side Effects:    None

 *

 * Overview:        This routine checks the setup data packet to see if it

 *                  knows how to handle it

 *

 * Note:            None

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

void USBCheckCDCRequest(void)

{

    /*

     * If request recipient is not an interface then return

     */

    if(SetupPkt.Recipient != RCPT_INTF) return;

    /*

     * If request type is not class-specific then return

     */

    if(SetupPkt.RequestType != CLASS) return;

    /*

     * Interface ID must match interface numbers associated with

     * CDC class, else return

     */

    if((SetupPkt.bIntfID != CDC_COMM_INTF_ID)&&

       (SetupPkt.bIntfID != CDC_DATA_INTF_ID)) return;

    switch(SetupPkt.bRequest)

    {

        case SEND_ENCAPSULATED_COMMAND:

            ctrl_trf_session_owner = MUID_CDC;

            pSrc.bRam = (byte*)&dummy_encapsulated_cmd_response;

            usb_stat.ctrl_trf_mem = _RAM;

            LSB(wCount) = dummy_length;

            break;

        case GET_ENCAPSULATED_RESPONSE:

            ctrl_trf_session_owner = MUID_CDC;

            // Populate dummy_encapsulated_cmd_response first.

            pDst.bRam = (byte*)&dummy_encapsulated_cmd_response;

            break;

        case SET_COMM_FEATURE:                  // Optional

            break;

        case GET_COMM_FEATURE:                  // Optional

            break;

        case CLEAR_COMM_FEATURE:                // Optional

            break;

        case SET_LINE_CODING:

            ctrl_trf_session_owner = MUID_CDC;

            pDst.bRam = (byte*)&line_coding;    // Set destination

            break;

        case GET_LINE_CODING:

            ctrl_trf_session_owner = MUID_CDC;

            pSrc.bRam = (byte*)&line_coding;    // Set source

            usb_stat.ctrl_trf_mem = _RAM;       // Set memory type

            LSB(wCount) = LINE_CODING_LENGTH;   // Set data count

            break;

        case SET_CONTROL_LINE_STATE:

            ctrl_trf_session_owner = MUID_CDC;

            control_signal_bitmap._byte = LSB(SetupPkt.W_Value);

            break;

        case SEND_BREAK:                        // Optional

            break;

        default:

            break;

    }//end switch(SetupPkt.bRequest)

}//end USBCheckCDCRequest

/** U S E R  A P I ***********************************************************/

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

 * Function:        void CDCInitEP(void)

 *

 * PreCondition:    None

 *

 * Input:           None

 *

 * Output:          None

 *

 * Side Effects:    None

 *

 * Overview:        CDCInitEP initializes CDC endpoints, buffer descriptors,

 *                  internal state-machine, and variables.

 *                  It should be called after the USB host has sent out a

 *                  SET_CONFIGURATION request.

 *                  See USBStdSetCfgHandler() in usb9.c for examples.

 *

 * Note:            None

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

void CDCInitEP(void)

{

    //Abstract line coding information

    line_coding.dwDTERate._dword = 115200;      // baud rate

    line_coding.bCharFormat = 0x00;             // 1 stop bit

    line_coding.bParityType = 0x00;             // None

    line_coding.bDataBits = 0x08;               // 5,6,7,8, or 16

    cdc_trf_state = CDC_TX_READY;

    cdc_rx_len = 0;

    CDC_COMM_UEP = EP_IN|HSHK_EN;               // Enable 1 Comm pipe

    CDC_DATA_UEP = EP_OUT_IN|HSHK_EN;           // Enable 2 data pipes

    /*

     * Do not have to init Cnt of IN pipes here.

     * Reason:  Number of bytes to send to the host

     *          varies from one transaction to

     *          another. Cnt should equal the exact

     *          number of bytes to transmit for

     *          a given IN transaction.

     *          This number of bytes will only

     *          be known right before the data is

     *          sent.

     */

    CDC_INT_BD_IN.ADR = (byte*)&cdc_notice;     // Set buffer address

    CDC_INT_BD_IN.Stat._byte = _UCPU|_DAT1;     // Set status

    CDC_BULK_BD_OUT.Cnt = sizeof(cdc_data_rx);  // Set buffer size

    CDC_BULK_BD_OUT.ADR = (byte*)&cdc_data_rx;  // Set buffer address

    CDC_BULK_BD_OUT.Stat._byte = _USIE|_DAT0|_DTSEN;// Set status

    CDC_BULK_BD_IN.ADR = (byte*)&cdc_data_tx;   // Set buffer size

    CDC_BULK_BD_IN.Stat._byte = _UCPU|_DAT1;    // Set buffer address

}//end CDCInitEP

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

 * Function:        byte getsUSBUSART(char *buffer,

 *                                    byte len)

 *

 * PreCondition:    Value of input argument 'len' should be smaller than the

 *                  maximum endpoint size responsible for receiving bulk

 *                  data from USB host for CDC class.

 *                  Input argument 'buffer' should point to a buffer area that

 *                  is bigger or equal to the size specified by 'len'.

 *

 * Input:           buffer  : Pointer to where received bytes are to be stored

 *                  len     : The number of bytes expected.

 *

 * Output:          The number of bytes copied to buffer.

 *

 * Side Effects:    Publicly accessible variable cdc_rx_len is updated with

 *                  the number of bytes copied to buffer.

 *                  Once getsUSBUSART is called, subsequent retrieval of

 *                  cdc_rx_len can be done by calling macro mCDCGetRxLength().

 *

 * Overview:        getsUSBUSART copies a string of bytes received through

 *                  USB CDC Bulk OUT endpoint to a user's specified location. 

 *                  It is a non-blocking function. It does not wait

 *                  for data if there is no data available. Instead it returns

 *                  '0' to notify the caller that there is no data available.

 *

 * Note:            If the actual number of bytes received is larger than the

 *                  number of bytes expected (len), only the expected number

 *                  of bytes specified will be copied to buffer.

 *                  If the actual number of bytes received is smaller than the

 *                  number of bytes expected (len), only the actual number

 *                  of bytes received will be copied to buffer.

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

byte getsUSBUSART(char *buffer, byte len)

{

    cdc_rx_len = 0;

    if(!mCDCUsartRxIsBusy())

    {

        /*

         * Adjust the expected number of bytes to equal

         * the actual number of bytes received.

         */

        if(len > CDC_BULK_BD_OUT.Cnt)

            len = CDC_BULK_BD_OUT.Cnt;

        /*

         * Copy data from dual-ram buffer to user's buffer

         */

        for(cdc_rx_len = 0; cdc_rx_len < len; cdc_rx_len++)

            buffer[cdc_rx_len] = cdc_data_rx[cdc_rx_len];

        /*

         * Prepare dual-ram buffer for next OUT transaction

         */

        CDC_BULK_BD_OUT.Cnt = sizeof(cdc_data_rx);

        mUSBBufferReady(CDC_BULK_BD_OUT);

    }//end if

    return cdc_rx_len;

}//end getsUSBUSART

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

 * Function:        void putsUSBUSART(char *data)

 *

 * PreCondition:    cdc_trf_state must be in the CDC_TX_READY state.

 *                  

 *                  The string of characters pointed to by 'data' must equal

 *                  to or smaller than 255 bytes.

 *

 * Input:           data    : Pointer to a null-terminated string of data.

 *                            If a null character is not found, 255 bytes

 *                            of data will be transferred to the host.

 *

 * Output:          None

 *

 * Side Effects:    None

 *

 * Overview:        putsUSBUSART writes a string of data to the USB including

 *                  the null character. Use this version, 'puts', to transfer

 *                  data located in data memory.

 *

 * Note:            The transfer mechanism for device-to-host(put) is more

 *                  flexible than host-to-device(get). It can handle

 *                  a string of data larger than the maximum size of bulk IN

 *                  endpoint. A state machine is used to transfer a long

 *                  string of data over multiple USB transactions.

 *                  See CDCTxService() for more details.

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

void putsUSBUSART(char *data)

{

    byte len;

    /*

     * User should have checked that cdc_trf_state is in CDC_TX_READY state

     * before calling this function.

     * As a safety precaution, this fuction checks the state one more time

     * to make sure it does not override any pending transactions.

     *

     * Currently it just quits the routine without reporting any errors back

     * to the user.

     *

     * Bottomline: User MUST make sure that mUSBUSARTIsTxTrfReady()==1

     *             before calling this function!

     * Example:

     * if(mUSBUSARTIsTxTrfReady())

     *     putsUSBUSART(pData);

     *

     * IMPORTANT: Never use the following blocking while loop to wait:

     * while(!mUSBUSARTIsTxTrfReady())

     *     putsUSBUSART(pData);

     *

     * The whole firmware framework is written based on cooperative

     * multi-tasking and a blocking code is not acceptable.

     * Use a state machine instead.

     */

    if(cdc_trf_state != CDC_TX_READY) return;

    /*

     * While loop counts the number of bytes to send including the

     * null character.

     */

    len = 0;

    do

    {

        len++;

        if(len == 255) break;       // Break loop once max len is reached.

    }while(*data++);

    /*

     * Re-adjust pointer to its initial location

     */

    data-=len;

    /*

     * Second piece of information (length of data to send) is ready.

     * Call mUSBUSARTTxRam to setup the transfer.

     * The actual transfer process will be handled by CDCTxService(),

     * which should be called once per Main Program loop.

     */

    mUSBUSARTTxRam((byte*)data,len);     // See cdc.h

}//end putsUSBUSART

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

 * Function:        void putrsUSBUSART(const rom char *data)

 *

 * PreCondition:    cdc_trf_state must be in the CDC_TX_READY state.

 *                  

 *                  The string of characters pointed to by 'data' must equal

 *                  to or smaller than 255 bytes.

 *

 * Input:           data    : Pointer to a null-terminated string of data.

 *                            If a null character is not found, 255 bytes

 *                            of data will be transferred to the host.

 *

 * Output:          None

 *

 * Side Effects:    None

 *

 * Overview:        putrsUSBUSART writes a string of data to the USB including

 *                  the null character. Use this version, 'putrs', to transfer

 *                  data literals and data located in program memory.

 *

 * Note:            The transfer mechanism for device-to-host(put) is more

 *                  flexible than host-to-device(get). It can handle

 *                  a string of data larger than the maximum size of bulk IN

 *                  endpoint. A state machine is used to transfer a long

 *                  string of data over multiple USB transactions.

 *                  See CDCTxService() for more details.

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

void putrsUSBUSART(const rom char *data)

{

    byte len;

    /*

     * User should have checked that cdc_trf_state is in CDC_TX_READY state

     * before calling this function.

     * As a safety precaution, this fuction checks the state one more time

     * to make sure it does not override any pending transactions.

     *

     * Currently it just quits the routine without reporting any errors back

     * to the user.

     *

     * Bottomline: User MUST make sure that mUSBUSARTIsTxTrfReady()

     *             before calling this function!

     * Example:

     * if(mUSBUSARTIsTxTrfReady())

     *     putsUSBUSART(pData);

     *

     * IMPORTANT: Never use the following blocking while loop to wait:

     * while(cdc_trf_state != CDC_TX_READY)

     *     putsUSBUSART(pData);

     *

     * The whole firmware framework is written based on cooperative

     * multi-tasking and a blocking code is not acceptable.

     * Use a state machine instead.

     */

    if(cdc_trf_state != CDC_TX_READY) return;

    /*

     * While loop counts the number of bytes to send including the

     * null character.

     */

    len = 0;

    do

    {

        len++;

        if(len == 255) break;       // Break loop once max len is reached.

    }while(*data++);

    /*

     * Re-adjust pointer to its initial location

     */

    data-=len;

    /*

     * Second piece of information (length of data to send) is ready.

     * Call mUSBUSARTTxRom to setup the transfer.

     * The actual transfer process will be handled by CDCTxService(),

     * which should be called once per Main Program loop.

     */

    mUSBUSARTTxRom((rom byte*)data,len); // See cdc.h

}//end putrsUSBUSART

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

 * Function:        void CDCTxService(void)

 *

 * PreCondition:    None

 *

 * Input:           None

 *

 * Output:          None

 *

 * Side Effects:    None

 *

 * Overview:        CDCTxService handles device-to-host transaction(s).

 *                  This function should be called once per Main Program loop.

 *

 * Note:            None

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

void CDCTxService(void)

{

    byte byte_to_send;

    if(mCDCUsartTxIsBusy()) return;

    /*

     * Completing stage is necessary while [ mCDCUSartTxIsBusy()==1 ].

     * By having this stage, user can always check cdc_trf_state,

     * and not having to call mCDCUsartTxIsBusy() directly.

     */

    if(cdc_trf_state == CDC_TX_COMPLETING)

        cdc_trf_state = CDC_TX_READY;

    /*

     * If CDC_TX_READY state, nothing to do, just return.

     */

    if(cdc_trf_state == CDC_TX_READY) return;

    /*

     * If CDC_TX_BUSY_ZLP state, send zero length packet

     */

    if(cdc_trf_state == CDC_TX_BUSY_ZLP)

    {

        CDC_BULK_BD_IN.Cnt = 0;

        cdc_trf_state = CDC_TX_COMPLETING;

    }

    else if(cdc_trf_state == CDC_TX_BUSY)

    {

        /*

         * First, have to figure out how many byte of data to send.

         */

    	if(cdc_tx_len > sizeof(cdc_data_tx))

    	    byte_to_send = sizeof(cdc_data_tx);

    	else

    	    byte_to_send = cdc_tx_len;

        /*

         * Next, load the number of bytes to send to Cnt in buffer descriptor

         */

        CDC_BULK_BD_IN.Cnt = byte_to_send;

        /*

         * Subtract the number of bytes just about to be sent from the total.

         */

    	cdc_tx_len = cdc_tx_len - byte_to_send;

        pCDCDst.bRam = (byte*)&cdc_data_tx; // Set destination pointer

        if(cdc_mem_type == _ROM)            // Determine type of memory source

        {

            while(byte_to_send)

            {

                *pCDCDst.bRam = *pCDCSrc.bRom;

                pCDCDst.bRam++;

                pCDCSrc.bRom++;

                byte_to_send--;

            }//end while(byte_to_send)

        }

        else // _RAM

        {

            while(byte_to_send)

            {

                *pCDCDst.bRam = *pCDCSrc.bRam;

                pCDCDst.bRam++;

                pCDCSrc.bRam++;

                byte_to_send--;

            }//end while(byte_to_send._word)

        }//end if(cdc_mem_type...)

        /*

         * Lastly, determine if a zero length packet state is necessary.

         * See explanation in USB Specification 2.0: Section 5.8.3

         */

        if(cdc_tx_len == 0)

        {

            if(CDC_BULK_BD_IN.Cnt == sizeof(cdc_data_tx))

                cdc_trf_state = CDC_TX_BUSY_ZLP;

            else

                cdc_trf_state = CDC_TX_COMPLETING;

        }//end if(cdc_tx_len...)

    }//end if(cdc_tx_sate == CDC_TX_BUSY)

    /*

     * Both CDC_TX_BUSY and CDC_TX_BUSY_ZLP states use the following macro

     */

    mUSBBufferReady(CDC_BULK_BD_IN);

}//end CDCTxService

#endif //USB_USE_CDC

/** EOF cdc.c ****************************************************************/