loader_f30x.c

C8051F0XX引导装入程序考虑及举例

   FLKEY = 0xF1;                    // FLASH lock and key sequence 2

   // Erase the FLASH page at 0x1000
   *pagePointer = 0;                // initiate the erase
   
   PSCTL = 0;                       // MOVX writes target XRAM

   EA =  EA_state;                  // restore interrupt state

   f_valid = FALSE;                 // indicate that code is no longer valid
   code_erased = TRUE;              // indicate that FLASH has been erased
}

//-----------------------------------------------------------------------------
// receive_code
//-----------------------------------------------------------------------------
//
// This routine receives HEX records through the UART and writes the 
// function located at 0x1000.
//
// Hex Record Format:
//
// +--------+--------+------+-------+--------+------(n bytes)------+----------+
// | RECORD | RECLEN |    OFFSET    | RECORD |                     | CHECKSUM |
// |  MARK  |  (n)   |   (2 BYTES)  |  TYPE  |        DATA         |          |
// |  ':'   |        |              |        |                     |          |
// +--------+--------+------+-------+--------+------(n bytes)------+----------+
//
void receive_code(void)
{
   char xdata* data pwrite;               // pointer used for writing FLASH
   char code* data pread;                 // pointer used for reading FLASH
   unsigned int  len;                     // holds the HEX record length field
   char record_type;                      // holds the HEX record type field
   unsigned int offset;                   // holds the HEX record offset field
                                          // this is the starting address of
                                          // the code image contained in the 
                                          // record

   char checksum;                         // holds the HEX record checksum field
   char flash_checksum;                   // holds the checksum calculated after
                                          // the FLASH has been programmed
   bit EA_state;                          // temporary holder used to restore 
                                          // interrupts to their previous state

   char c;                                // temporary char
   int i;                                 // temporary int
       
   
   // make sure the flash page has been erased
   if(!code_erased){
      printf("\n*** At least one FLASH page must be erased prior to ");
      printf("this operation.\n");
      return;
   }
   
   // wait for the user to send HEX file

   do{
      
      while( c = _getkey() != ':' );
      
      // get the length
      len = hex2char();
      
      // get the offset
      offset = hex2char();
      offset <<= 8;
      offset |= hex2char();
      
      
      // get the record type
      record_type = hex2char();
      if( record_type != 0 && record_type != 1 ){
         printf("\n*** Cannot decode HEX file.\n"); 
         return;
      }      

      EA_state = EA;                      // save the interrupt enable bit state

      EA = 0;                             // disable interrupts (precautionary)   
      PSCTL = 1;                          // MOVX writes to FLASH

      pwrite = (char xdata*) offset;      // initialize the write pointer
            
      code_erased = FALSE;                // clear the code_erased flag
           
      // write the record into flash
      for( i = 0; i < len; i++){
         FLKEY = 0xA5;                    // FLASH lock and key sequence 1
         FLKEY = 0xF1;                    // FLASH lock and key sequence 2
         *pwrite = hex2char();            // write one byte to FLASH
         pwrite++;                        // increment FLASH write pointer
      }
      
      PSCTL = 0;                          // MOVX writes target XRAM
      EA = EA_state;                      // restore interrupts to previous state
      
      // verify the checksum
      pread =  (char code*) offset;       // initialize the read pointer
      checksum = hex2char();              // get the HEX record checksum field
      flash_checksum = 0;                 // set the flash_checksum to zero
      
      // add the data field stored in FLASH to the checksum
      for( i = 0; i < len; i++)
      {
         flash_checksum += *pread++;
      } 
      
      // add the remaining fields
      flash_checksum += len;
      flash_checksum += (char) (offset >> 8);
      flash_checksum += (char) (offset & 0x00FF);
      flash_checksum += record_type;
      flash_checksum += checksum;
      
      // verify the checksum (the flash_checksum should equal zero)
      if(flash_checksum != 0){
         printf("*** Checksum failed, try again.");
         return;
      }
      
      
   } while(record_type != 1); 

   
   f_valid = TRUE;                  // flag that f() is valid
   

   _getkey();                       // clear carriage return
                                    // from the input stream

   printf("\nReceived OK.\n"); 
}

//-----------------------------------------------------------------------------
// Initialization Subroutines
//-----------------------------------------------------------------------------

//-----------------------------------------------------------------------------
// SYSCLK_Init
//-----------------------------------------------------------------------------
//
// This routine initializes the system clock to use the internal 24.5MHz 
// oscillator as its clock source.  Enables missing clock detector reset. Also
// configures and enables the external crystal oscillator.
//
void SYSCLK_Init (void)
{
   
   OSCICN |= 0x03;                     // configure internal oscillator for
                                       // its maximum frequency
   RSTSRC = 0x06;                      // enable missing clock detector and
                                       // VDD monitor
 
}

//-----------------------------------------------------------------------------
// PORT_Init
//-----------------------------------------------------------------------------
//
// Configure the Crossbar and GPIO ports.
// P0.0 - 
// P0.1 -
// P0.2 - LED (push-pull)
// P0.3 - SW2
// P0.4 - UART TX (push-pull)
// P0.5 - UART RX
// P0.6 - 
// P0.7 - C2D
//
void PORT_Init (void)
{
   XBR0    = 0x04;                     // P0.2 skipped by the crossbar
   XBR1    = 0x03;                     // UART0 TX and RX pins enabled
   XBR2    = 0x40;                     // Enable crossbar and weak pull-ups
   P0MDIN &= ~0x00;                    // no analog inputs
   P0MDOUT |= 0x14;                    // enable TX0 and P0.2 as 
                                       // push-pull output
}

//-----------------------------------------------------------------------------
// UART0_Init
//-----------------------------------------------------------------------------
//
// Configure the UART0 using Timer1, for <BAUDRATE> and 8-N-1.
//
void UART0_Init (void)
{
   SCON0 = 0x10;                       // SCON0: 8-bit variable bit rate
                                       //        level of STOP bit is ignored
                                       //        RX enabled
                                       //        ninth bits are zeros
                                       //        clear RI0 and TI0 bits
   if (SYSCLK/BAUDRATE/2/256 < 1) {
      TH1 = -(SYSCLK/BAUDRATE/2);
      CKCON |= 0x10;                   // T1M = 1; SCA1:0 = xx
   } else if (SYSCLK/BAUDRATE/2/256 < 4) {
      TH1 = -(SYSCLK/BAUDRATE/2/4);
      CKCON |=  0x01;                  // T1M = 0; SCA1:0 = 01
      CKCON &= ~0x12;
   } else if (SYSCLK/BAUDRATE/2/256 < 12) {
      TH1 = -(SYSCLK/BAUDRATE/2/12);
      CKCON &= ~0x13;                  // T1M = 0; SCA1:0 = 00
   } else {
      TH1 = -(SYSCLK/BAUDRATE/2/48);
      CKCON |=  0x02;                  // T1M = 0; SCA1:0 = 10
      CKCON &= ~0x11;
   }

   TL1 = 0xff;                         // set Timer1 to overflow immediately
   TMOD &= ~0xf0;                      // TMOD: timer 1 in 8-bit autoreload
   TMOD |=  0x20;                       
   TR1 = 1;                            // START Timer1
   TI0 = 1;                            // Indicate TX0 ready
}