//-----------------------------------------------------------------------------
// F12x_INIT_1.c
//-----------------------------------------------------------------------------
// Copyright 2002 Cygnal Integrated Products, Inc.
//
// AUTH: FB
// DATE: 19 SEP 02
//
// This file contains example initialization routines for the C8051F12x series
// of devices. 
//
// This program uses the the 24.5 MHz internal oscillator multiplied by two 
// for an effective SYSCLK of 49 MHz. This program also initializes and uses
// UART1 at <BAUDRATE> bits per second.
//
//
// Target: C8051F12x
// Tool chain: KEIL C51 6.03 / KEIL EVAL C51
//

//-----------------------------------------------------------------------------
// Includes
//-----------------------------------------------------------------------------
#include <c8051f120.h>                 // SFR declarations
#include <stdio.h>                     // printf() and getchar()

//-----------------------------------------------------------------------------
// 16-bit SFR Definitions for 'F12x
//-----------------------------------------------------------------------------

sfr16 DP       = 0x82;                 // data pointer
sfr16 ADC0     = 0xbe;                 // ADC0 data
sfr16 ADC0GT   = 0xc4;                 // ADC0 greater than window
sfr16 ADC0LT   = 0xc6;                 // ADC0 less than window
sfr16 RCAP2    = 0xca;                 // Timer2 capture/reload
sfr16 RCAP3    = 0xca;                 // Timer3 capture/reload
sfr16 RCAP4    = 0xca;                 // Timer4 capture/reload
sfr16 TMR2     = 0xcc;                 // Timer2
sfr16 TMR3     = 0xcc;                 // Timer3
sfr16 TMR4     = 0xcc;                 // Timer4
sfr16 DAC0     = 0xd2;                 // DAC0 data
sfr16 DAC1     = 0xd2;                 // DAC1 data
sfr16 PCA0CP5  = 0xe1;                 // PCA0 Module 5 capture
sfr16 PCA0CP2  = 0xe9;                 // PCA0 Module 2 capture
sfr16 PCA0CP3  = 0xeb;                 // PCA0 Module 3 capture
sfr16 PCA0CP4  = 0xed;                 // PCA0 Module 4 capture
sfr16 PCA0     = 0xf9;                 // PCA0 counter
sfr16 PCA0CP0  = 0xfb;                 // PCA0 Module 0 capture
sfr16 PCA0CP1  = 0xfd;                 // PCA0 Module 1 capture

//-----------------------------------------------------------------------------
// Global CONSTANTS
//-----------------------------------------------------------------------------
#define TRUE         1
#define FALSE        0

#define INTCLK       24500000          // Internal oscillator frequency in Hz
#define SYSCLK       49000000          // Output of PLL derived from (INTCLK*2)
#define BAUDRATE     115200            // Baud rate of UART in bps

sbit LED = P1^6;                       // LED='1' means ON
sbit SW2 = P3^7;                       // SW2='0' means switch pressed


//-----------------------------------------------------------------------------
// Function PROTOTYPES
//-----------------------------------------------------------------------------
void main(void);
void SYSCLK_Init(void);
void PORT_Init(void);
void UART1_Init (void);

//-----------------------------------------------------------------------------
// MAIN Routine
//-----------------------------------------------------------------------------

void main (void) 
{

   WDTCN = 0xde;                       // disable watchdog timer
   WDTCN = 0xad;

   PORT_Init ();                       // initialize crossbar and GPIO
   SYSCLK_Init ();                     // initialize oscillator
   UART1_Init ();                      // initialize UART1
   

   SFRPAGE = UART1_PAGE;               // Direct printf output to UART1
   printf("Hello\n");                  // Print a string

   while(1);

} 

//-----------------------------------------------------------------------------
// Initialization Routines
//-----------------------------------------------------------------------------

//-----------------------------------------------------------------------------
// SYSCLK_Init
//-----------------------------------------------------------------------------
//
// This routine initializes the system clock to use the internal oscillator
// at 24.5 MHz multiplied by two using the PLL.
//
void SYSCLK_Init (void)
{
   int i;                           // software timer

   char SFRPAGE_SAVE = SFRPAGE;     // Save Current SFR page

   SFRPAGE = CONFIG_PAGE;           // set SFR page

   OSCICN = 0x83;                   // set internal oscillator to run
                                    // at its maximum frequency

   CLKSEL = 0x00;                   // Select the internal osc. as
                                    // the SYSCLK source
   
   //Turn on the PLL and increase the system clock by a factor of M/N = 2
   SFRPAGE = CONFIG_PAGE;
   
   PLL0CN  = 0x00;                  // Set internal osc. as PLL source
   SFRPAGE = LEGACY_PAGE;
   FLSCL   = 0x10;                  // Set FLASH read time for 50MHz clk
                                    // or less
   SFRPAGE = CONFIG_PAGE;
   PLL0CN |= 0x01;                  // Enable Power to PLL
   PLL0DIV = 0x01;                  // Set Pre-divide value to N (N = 1)
   PLL0FLT = 0x01;                  // Set the PLL filter register for 
                                    // a reference clock from 19 - 30 MHz
                                    // and an output clock from 45 - 80 MHz 
   PLL0MUL = 0x02;                  // Multiply SYSCLK by M (M = 2)
   
   for (i=0; i < 256; i++) ;        // Wait at least 5us
   PLL0CN  |= 0x02;                 // Enable the PLL
   while(!(PLL0CN & 0x10));         // Wait until PLL frequency is locked
   CLKSEL  = 0x02;                  // Select PLL as SYSCLK source

   SFRPAGE = SFRPAGE_SAVE;          // Restore SFR page
}


//-----------------------------------------------------------------------------
// PORT_Init
//-----------------------------------------------------------------------------
//
// This routine configures the crossbar and GPIO ports.
//
void PORT_Init (void)
{
   char SFRPAGE_SAVE = SFRPAGE;     // Save Current SFR page
   
   SFRPAGE = CONFIG_PAGE;           // set SFR page

   XBR0     = 0x00;                 
   XBR1     = 0x00;
   XBR2     = 0x44;                 // Enable crossbar and weak pull-up
                                    // Enable UART1

   P0MDOUT |= 0x01;                 // Set TX1 pin to push-pull
   P1MDOUT |= 0x40;                 // Set P1.6(LED) to push-pull
   
   SFRPAGE = SFRPAGE_SAVE;          // Restore SFR page
}

//-----------------------------------------------------------------------------
// UART1_Init
//-----------------------------------------------------------------------------
//
// Configure the UART1 using Timer1, for <baudrate> and 8-N-1.
//
void UART1_Init (void)
{
   char SFRPAGE_SAVE = SFRPAGE;     // Save Current SFR page
   
   SFRPAGE = UART1_PAGE;
   SCON1   = 0x10;                  // SCON1: mode 0, 8-bit UART, enable RX
   
   SFRPAGE = TIMER01_PAGE;
   TMOD   &= ~0xF0;
   TMOD   |=  0x20;                 // TMOD: timer 1, mode 2, 8-bit reload
   
   
   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 &= ~0x13;               // Clear all T1 related bits
      CKCON |=  0x01;               // T1M = 0; SCA1:0 = 01
   } 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 &= ~0x13;               // Clear all T1 related bits
      CKCON |=  0x02;               // T1M = 0; SCA1:0 = 10
   }   

   TL1 = TH1;                       // initialize Timer1
   TR1 = 1;                         // start Timer1  
   
   SFRPAGE = UART1_PAGE;
   TI1 = 1;                         // Indicate TX1 ready

   SFRPAGE = SFRPAGE_SAVE;          // Restore SFR page

}