File content as of revision 5:b40a6fd3a334:

/** 

Copyright 2014 John Bailey
   
Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.

*/

#include "XBeeDevice.hpp"

/** Number of bytes we need to 'peek' into the receive buffer in order to retrieve the 
    payload length */
#define INITIAL_PEEK_LEN (3U)
    
/** Enum of bytes with a special meaning when communicating with the XBee in API
    mode.  In escaped mode, these are the bytes that need to be escaped */
typedef enum
{
    XBEE_SB_XON             = 0x11,
    XBEE_SB_XOFF            = 0x13,
    XBEE_SB_FRAME_DELIMITER = 0x7E,
    XBEE_SB_ESCAPE          = 0x7D
} XBeeSerialSpecialBytes_e;

/** ASCII command to the XBee to request API mode 2 */
const char api_mode2_cmd[] = { 'A', 'T', 'A', 'P', ' ', '2', '\r' };

/** ASCII command to the XBee to request that it exit command mode */
const char exit_cmd_mode_cmd[] = { 'A', 'T', 'C', 'N', '\r' };

XBeeDevice::XBeeDevice( PinName p_tx, PinName p_rx, PinName p_rts, PinName p_cts ): m_if( p_tx, p_rx )
{
    m_escape = true;
    m_inAtCmdMode = false;
    m_rxMsgLastWasEsc = false;
    
    /* Can only do flow control on devices which support it */
#if defined ( DEVICE_SERIAL_FC )
    /* TODO: need rts and cts both set? */
    m_if.set_flow_control( mbed::SerialBase::Flow.RTSCTS, p_rts, p_cts );
#endif

    /* Attach RX call-back to the serial interface */
    m_if.attach( this, &XBeeDevice::if_rx, Serial::RxIrq); 
}

XBeeDevice::~XBeeDevice( void )
{
    /* Iterate all of the decoders and un-register them */
    for( FixedLengthList<XBeeApiFrameDecoder*, XBEEAPI_CONFIG_DECODER_LIST_SIZE>::iterator it = m_decoders.begin() ;
         it != m_decoders.end();
         ++it ) {
        (*it)->unregisterCallback();
    }
}

void XBeeDevice::if_rx( void )
{
    /* Keep going while there are bytes to be read */
    while(m_if.readable()) {
        
        uint8_t c = m_if.getc();
        
        /* Sanity check that if we're starting from an empty buffer the byte that we're
           receiving is a frame delimiter */
        if(( m_inAtCmdMode ) ||
           (( c == XBEE_SB_FRAME_DELIMITER ) ||
            ( m_rxBuff.getSize() ))) 
        {
            /* If it's an escape character we want to de-code the escape, so flag
               that we have a pending escape but don't modify the rx buffer */
            if( m_escape &&
               ( c == XBEE_SB_ESCAPE ))
            {
                m_rxMsgLastWasEsc = true;
            }
            else
            {
                if( m_rxMsgLastWasEsc ) {
                    c = c ^ 0x20;  
                    m_rxMsgLastWasEsc = false;
                }
                m_rxBuff.write( &c, 1 );
            }
        } else {
            /* TODO */    
        }
    }
    
    if( m_inAtCmdMode ) 
    {
        m_rxMsgLastWasEsc = false;
    } 
 
    checkRxDecode();
}
    
void XBeeDevice::checkRxDecode( void )
{
    /* Get an initial portion of data from the read buffer so that the message length can be determined */
    uint8_t buff[INITIAL_PEEK_LEN];
    uint16_t len = m_rxBuff.peek( buff, INITIAL_PEEK_LEN );    
    
    if((len >= INITIAL_PEEK_LEN ) &&
       (buff[ XBEE_CMD_POSN_SDELIM ] == XBEE_SB_FRAME_DELIMITER ))
    {
        /* Try and get enough data to cover the whole message */
        /* TODO: Magic number */
        const uint16_t cmdLen = MSG_LEN_IN_BUFFER( buff ) + XBEE_API_FRAME_OVERHEAD;
        uint8_t cmdBuff[cmdLen];
        uint16_t len = m_rxBuff.peek( cmdBuff, cmdLen );    

        if( len >= cmdLen )
        {
            /* TODO: Verify checksum */
            
            /* Iterate all of the decoders */
            for( FixedLengthList<XBeeApiFrameDecoder*, XBEEAPI_CONFIG_DECODER_LIST_SIZE>::iterator it = m_decoders.begin() ;
                 it != m_decoders.end();
                 ++it ) {

                bool processed = (*it)->decodeCallback( cmdBuff, cmdLen );
                if( processed )
                {
                    break;
                }
            }            
            /* Remove the data from the receive buffer - either it was decoded (all well and good)
               or it wasn't, in which case we need to get rid of it to prevent it from jamming
               up the message queue */
            m_rxBuff.chomp( cmdLen );
        }
    }
}

bool XBeeDevice::registerDecoder( XBeeApiFrameDecoder* const p_decoder )
{
    bool ret_val = false;
    if( p_decoder != NULL )
    {
        if( !m_decoders.inList( p_decoder ) ) {
            m_decoders.push( p_decoder );   
            p_decoder->registerCallback( this );
            ret_val = true;
        }
    }
    return ret_val;
}
     
bool XBeeDevice::unregisterDecoder( XBeeApiFrameDecoder* const p_decoder )
{
    bool ret_val = false;
    if( p_decoder != NULL )
    {
        /* Iterate all of the decoders */
        for( FixedLengthList<XBeeApiFrameDecoder*, XBEEAPI_CONFIG_DECODER_LIST_SIZE>::iterator it = m_decoders.begin() ;
             it != m_decoders.end();
             ++it ) {
            if( *it == p_decoder ) {
                p_decoder->unregisterCallback();
                /* TODO: Actually remove the item from m_decoders! */
                ret_val = true;   
            }
        }
    }
    return ret_val;
}

void XBeeDevice::SendFrame( const XBeeApiFrame* const p_cmd )
{
    uint8_t sum = 0U;
    uint16_t len;
    uint16_t i;
    const uint8_t* cmdData;
 
#if defined  XBEEAPI_CONFIG_USING_RTOS
    m_ifMutex.lock();
#endif

    xbeeWrite( XBEE_SB_FRAME_DELIMITER, false );
    
    len = p_cmd->getCmdLen();
    xbeeWrite((uint8_t)(len >> 8U));
    xbeeWrite((uint8_t)(len & 0xFF));

    sum += xbeeWrite((uint8_t)p_cmd->getApiId());

    cmdData = p_cmd->getDataPtr();

    for( i = 0;
         i < (len-1);
         i++ )
    {
        sum += xbeeWrite(cmdData[i]);
    }
    
    /* Checksum is 0xFF - summation of bytes (excluding delimiter and length) */
    xbeeWrite( (uint8_t)0xFFU - sum );
    
    fflush( m_if );
    
#if defined  XBEEAPI_CONFIG_USING_RTOS
    m_ifMutex.unlock();
#endif
}

uint8_t XBeeDevice::xbeeWrite( uint8_t p_byte, bool p_doEscape )
{
    uint8_t c_sum = 0;
    
    if (p_doEscape && m_escape && 
        ((p_byte == XBEE_SB_FRAME_DELIMITER ) ||
         (p_byte == XBEE_SB_ESCAPE ) || 
         (p_byte == XBEE_SB_XON ) || 
         (p_byte == XBEE_SB_XOFF))) 
    {
        #if 0
        m_if.printf("%02x ",XBEE_SB_ESCAPE);
        m_if.printf("%02x ",p_byte ^ 0x20);
        #else
        m_if.putc(XBEE_SB_ESCAPE);
        m_if.putc(p_byte ^ 0x20);
        #endif
        c_sum += XBEE_SB_ESCAPE;
        c_sum += p_byte ^ 0x20;
    } else {
        #if 0
        m_if.printf("%02x ",p_byte);
        #else
        m_if.putc(p_byte);
        #endif
        c_sum += p_byte;
    }
    return c_sum;
}

#define IS_OK( _b ) (( _b[ 0 ] == 'O' ) && ( _b[ 1 ] == 'K' ) && ( _b[ 2 ] == '\r' ))
#define OK_LEN (3U)

XBeeDevice::XBeeDeviceReturn_t XBeeDevice::SendFrame( const char* const p_dat, size_t p_len, int p_wait_ms )
{
    XBeeDeviceReturn_t ret_val;

    if( m_inAtCmdMode )
    {
#if defined  XBEEAPI_CONFIG_USING_RTOS
        m_ifMutex.lock();
#endif
        for( size_t i = 0;
             i < p_len;
             i++ ) {
            m_if.putc(p_dat[i]);
        }
        
        fflush( m_if );
                
        wait_ms( p_wait_ms );
                
        /* Check the response for the OK indicator */
        if( m_rxBuff.getSize() == OK_LEN )
        {
            uint8_t ok_buff[OK_LEN];
            m_rxBuff.read( ok_buff, OK_LEN );
                    
            if( IS_OK( ok_buff ))
            {
                ret_val = XBEEDEVICE_OK;
            } 
            else 
            {
                ret_val = XBEEDEVICE_UNEXPECTED_DATA;                    
            }
        }
        else
        {
            ret_val = XBEEDEVICE_UNEXPECTED_LENGTH;
        }
#if defined  XBEEAPI_CONFIG_USING_RTOS
        m_ifMutex.unlock();
#endif
    } 
    else 
    {
        ret_val = XBEEDEVICE_WRONG_MODE;            
    }
    return ret_val;
}

XBeeDevice::XBeeDeviceReturn_t XBeeDevice::setUpApi( void )
{
    XBeeDeviceReturn_t ret_val;
    
    /* Wait for the guard period before transmitting command sequence */
    wait_ms( XBEEAPI_CONFIG_GUARDPERIOD_MS );
    
    m_inAtCmdMode = true;
    
    /* Request to enter command mode */
    /* TODO: Magic number */
    ret_val = SendFrame("+++", 3, 3000);

    /* Everything OK with last request? */
    if( ret_val == XBEEDEVICE_OK )
    {
        wait_ms( XBEEAPI_CONFIG_GUARDPERIOD_MS );
        
        /* API mode 2 please! */
        ret_val = SendFrame(api_mode2_cmd,sizeof(api_mode2_cmd));
    }

    /* Everything OK with last request? */
    if( ret_val == XBEEDEVICE_OK )
    {
        /* Exit command mode, back to API mode */
        ret_val = SendFrame(exit_cmd_mode_cmd,sizeof(exit_cmd_mode_cmd));
    }
    
    m_inAtCmdMode = false;
    
    return ret_val;
}

#if defined XBEEAPI_CONFIG_ENABLE_DEVELOPER

#define PRINTABLE_ASCII_FIRST 32U
#define PRINTABLE_ASCII_LAST 126U

void XBeeDevice::dumpRxBuffer( Stream* p_buf, const bool p_hexView )
{
    uint8_t c;
    while( m_rxBuff.getSize() ) {
        if( m_rxBuff.read( &c, 1 ) ) {
            if( p_hexView ) {
                uint8_t a = '-';
                if(( c>=PRINTABLE_ASCII_FIRST ) && (c<=PRINTABLE_ASCII_LAST)) {
                    a = c;
                }
                p_buf->printf("0x%02x (%c) ",c,a);
            } else {
                p_buf->printf("%c",c);
                if( c == '\r' ) {
                    p_buf->printf("\n");   
                }
            }
        }
    }
}

#endif