/****************************************************************************************
|  Description: demo program application source file
|    File Name: main.c
|
|----------------------------------------------------------------------------------------
|                          C O P Y R I G H T
|----------------------------------------------------------------------------------------
|   Copyright (c) 2011  by Feaser    http://www.feaser.com    All rights reserved
|
|----------------------------------------------------------------------------------------
|                            L I C E N S E
|----------------------------------------------------------------------------------------
| This file is part of OpenBLT. OpenBLT 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.
|
| OpenBLT 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 OpenBLT.
| If not, see <http://www.gnu.org/licenses/>.
|
| A special exception to the GPL is included to allow you to distribute a combined work 
| that includes OpenBLT without being obliged to provide the source code for any 
| proprietary components. The exception text is included at the bottom of the license
| file <license.html>.
| 
****************************************************************************************/

/****************************************************************************************
* Include files
****************************************************************************************/
#include "header.h"                                    /* generic header               */


/****************************************************************************************
* Function prototypes
****************************************************************************************/
static void Init(void);


/****************************************************************************************
** NAME:           main
** PARAMETER:      none
** RETURN VALUE:   program return code
** DESCRIPTION:    This is the entry point for the bootloader application and is called 
**                 by the reset interrupt vector after the C-startup routines executed.
**
****************************************************************************************/
int main(void)
{
  /* initialize the microcontroller */
  Init();

  /* initialize the bootloader interface */
  BootComInit();

  /* start the infinite program loop */
  while (1)
  {
    /* toggle LED with a fixed frequency */
    LedToggle();
    
    /* check for bootloader activation request */
    BootComCheckActivationRequest();
  }

  /* program should never get here */
  return 0;
} /*** end of main ***/


/****************************************************************************************
** NAME:           Init
** PARAMETER:      none
** RETURN VALUE:   none
** DESCRIPTION:    Initializes the microcontroller. The Fpll is set to 60MHz and Fvpb is
**                 configured equal to Fpll. The GPIO pin of the status LED is configured
**                 as digital output.
**
****************************************************************************************/
static void Init(void)
{
  unsigned char m_sel;                                /* pll multiplier register value */
  unsigned char pll_dividers[] = { 1, 2, 4, 8 };      /* possible pll dividers         */
  unsigned char p_sel_cnt;                            /* loop counter to find p_sel    */
  unsigned long f_cco;                                /* current controller oscillator */
    
  /* calculate MSEL: M = round(Fcclk / Fosc) */
  m_sel = (BOOT_CPU_SYSTEM_SPEED_KHZ + ((BOOT_CPU_XTAL_SPEED_KHZ+1)/2)) / \
           BOOT_CPU_XTAL_SPEED_KHZ;
  /* value for the PLLCFG register is -1 */
  m_sel--;
  
  /* find PSEL value so that Fcco(= Fcclk * 2 * P) is in the 156000..320000 kHz range. */
  for (p_sel_cnt=0; p_sel_cnt<sizeof(pll_dividers)/sizeof(pll_dividers[0]); p_sel_cnt++)
  {
    /* check f_cco with this pll divider */  
    f_cco = BOOT_CPU_SYSTEM_SPEED_KHZ * 2 * pll_dividers[p_sel_cnt];
    if ( (f_cco >= 156000) && (f_cco <= 320000) )
    {
      /* found a valid pll divider value */
      break;
    }
  }

  /* set multiplier and divider values */
  PLLCFG  = (p_sel_cnt << 5) | m_sel;
  PLLFEED = 0xAA;
  PLLFEED = 0x55;
  /* enable the PLL */
  PLLCON  = 0x1;
  PLLFEED = 0xAA;
  PLLFEED = 0x55;
  /* wait for the PLL to lock to set frequency */
  while(!(PLLSTAT & 0x400)) { ; }  
  /* connect the PLL as the clock source */
  PLLCON  = 0x3;
  PLLFEED = 0xAA;
  PLLFEED = 0x55;
  /* enable MAM and set number of clocks used for Flash memory fetch. Recommended:
   *   Fcclk >= 60 MHz: 4 clock cycles  
   *   Fcclk >= 40 MHz: 3 clock cycles  
   *   Fcclk >= 20 MHz: 2 clock cycles  
   *   Fcclk <  20 MHz: 1 clock cycle
   */
  MAMCR   = 0x0;
#if (BOOT_CPU_SYSTEM_SPEED_KHZ >= 60)
  MAMTIM  = 4;
#elif (BOOT_CPU_SYSTEM_SPEED_KHZ >= 40)  
  MAMTIM  = 3;
#elif (BOOT_CPU_SYSTEM_SPEED_KHZ >= 20)  
  MAMTIM  = 2;
#else
  MAMTIM  = 1;
#endif  
  MAMCR   = 0x2;
  /* setting peripheral Clock (pclk) to System Clock (cclk) */
  VPBDIV  = 0x1;
  /* init the led driver */
  LedInit();
  /* init the timer driver */
  TimerInit();
  /* enable IRQ's */
  IrqInterruptEnable();
} /*** end of Init ***/


/*********************************** end of main.c *************************************/