temp_3.c

cygnsl公司的c8051f04x的一个can应用实例。可以直接应用或参考。

//-----------------------------------------------------------------------------
// Temp_3.c
//-----------------------------------------------------------------------------
// Copyright (C) 2004 Silicon Laboratories, Inc.
//
// AUTH: BW / FB
// DATE: 06 FEB 03
//
// This program prints the C8051F040 die temperature out the hardware
// UART at 115200bps. This example uses the internal 24.5MHz oscillator.
//
// The ADC is configured to look at the on-chip temp sensor.  The sampling
// rate of the ADC is determined by the constant <SAMPLE_RATE>, which is given
// in Hz.
//
// The ADC0 End of Conversion Interrupt Handler retrieves the sample
// from the ADC and adds it to a running accumulator.  Every <INT_DEC>
// samples, the ADC updates and stores its result in the global variable
// <temperature>, which holds the current temperature in hundredths of a
// degree.  The sampling technique of adding a set of values and
// decimating them (posting results every (n)th sample) is called 'integrate
// and dump.'  It is easy to implement and requires very few resources.
//
// For each power of 4 of <INT_DEC>, you gain 1 bit of effective resolution.
// For example, <INT_DEC> = 256 gain you 4 bits of resolution: 4^4 = 256.
//
// Also note that the ADC0 is configured for 'LEFT' justified mode.  In this
// mode, the MSB of the ADC word is located in the MSB position of the ADC0
// high byte.  Using the data in this way makes the magnitude of the resulting
// code independent of the number of bits in the ADC (12- and 10-bits behave
// the same).
//
// Target: C8051F04x
// Tool chain: KEIL C51 6.03 / KEIL EVAL C51
//

//-----------------------------------------------------------------------------
// Includes
//-----------------------------------------------------------------------------

#include <c8051f040.h>                 // SFR declarations
#include <stdio.h>

//-----------------------------------------------------------------------------
// 16-bit SFR Definitions for 'F04x
//-----------------------------------------------------------------------------

sfr16 DP       = 0x82;                 // data pointer
sfr16 RCAP2    = 0xCA;                 // Timer2 reload/capture value
sfr16 RCAP3    = 0xCA;                 // Timer3 reload/capture value
sfr16 RCAP4    = 0xCA;                 // Timer4 reload/capture value
sfr16 TMR2     = 0xCC;                 // Timer2 counter/timer
sfr16 TMR3     = 0xCC;                 // Timer3 counter/timer
sfr16 TMR4     = 0xCC;                 // Timer4 counter/timer
sfr16 ADC0     = 0xBE;                 // ADC0 data
sfr16 ADC0GT   = 0xC4;                 // ADC0 greater than window
sfr16 ADC0LT   = 0xC6;                 // ADC0 less than window
sfr16 DAC0     = 0xD2;                 // DAC0 data
sfr16 DAC1     = 0xD2;                 // DAC1 data
sfr16 CAN0DAT  = 0xD8;                 // CAN data window

//-----------------------------------------------------------------------------
// Global CONSTANTS
//-----------------------------------------------------------------------------

#define BAUDRATE     115200            // Baud rate of UART in bps
#define SYSCLK       24500000          // Internal oscillator frequency in Hz
#define SAMPLE_RATE  50000             // Sample frequency in Hz
#define INT_DEC      256               // integrate and decimate ratio

sbit LED = P1^6;                       // LED='1' means ON
sbit SW1 = P3^7;                       // SW1='0' means switch pressed

//-----------------------------------------------------------------------------
// Function PROTOTYPES
//-----------------------------------------------------------------------------

void SYSCLK_Init (void);
void PORT_Init (void);
void UART1_Init (void);
void ADC0_Init (void);
void Timer3_Init (int counts);
void ADC0_ISR (void);
void wait_ms (int ms);
//-----------------------------------------------------------------------------
// Global VARIABLES
//-----------------------------------------------------------------------------

long result;                           // ADC0 decimated value

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

void main (void) {
   long temperature;                   // temperature in hundredths of a
                                       // degree C
   int temp_int, temp_frac;            // integer and fractional portions of
                                       // temperature

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

   SYSCLK_Init ();                     // initialize oscillator
   PORT_Init ();                       // initialize crossbar and GPIO
   UART1_Init ();                      // initialize UART1
   Timer3_Init (SYSCLK/SAMPLE_RATE);   // initialize Timer3 to overflow at
                                       // sample rate

   ADC0_Init ();                       // init ADC

   SFRPAGE = ADC0_PAGE;
   AD0EN = 1;                          // enable ADC

   EA = 1;                             // Enable global interrupts

   while (1) {
      EA = 0;                          // disable interrupts
      temperature = result;
      EA = 1;                          // re-enable interrupts

      // calculate temperature in hundredths of a degree
      temperature = temperature - 42380;
      temperature = (temperature * 100L) / 156;
      temp_int = temperature / 100;
      temp_frac = temperature - (temp_int * 100);

      SFRPAGE = UART1_PAGE;
      printf ("Temperature is %+02d.%02d\n", temp_int, temp_frac);

      SFRPAGE = CONFIG_PAGE;
      LED = ~SW1;                      // LED reflects state of switch

      wait_ms(50);                     // wait 50 milliseconds
   }
}

//-----------------------------------------------------------------------------
// Support Subroutines
//-----------------------------------------------------------------------------

//-----------------------------------------------------------------------------
// wait_ms
//-----------------------------------------------------------------------------
//
// This routine inserts a delay of <ms> milliseconds.
//
void wait_ms (int ms)
{
   char SFRPAGE_SAVE = SFRPAGE;        // Save Current SFR page

   SFRPAGE = TMR2_PAGE;

   TMR2CN = 0x00;                      // Stop Timer3; Clear TF3;
   TMR2CF = 0x00;                      // use SYSCLK/12 as timebase

   RCAP2 = -(SYSCLK/1000/12);          // Timer 2 overflows at 1 kHz
   TMR2 = RCAP2;

   ET2 = 0;                            // Disable Timer 2 interrupts

   TR2 = 1;                            // Start Timer 2

   while(ms){
      TF2 = 0;
      while(!TF2);                     // wait until timer overflows
      ms--;                            // decrement ms
   }

   TR2 = 0;                            // Stop Timer 2

   SFRPAGE = SFRPAGE_SAVE;             // Restore SFRPAGE
}

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

//-----------------------------------------------------------------------------
// SYSCLK_Init
//-----------------------------------------------------------------------------
//
// This routine initializes the system clock to use the internal oscillator
// at 24.5 MHz.
//
void SYSCLK_Init (void)
{
   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

   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

}

//-----------------------------------------------------------------------------
// ADC0_Init
//-----------------------------------------------------------------------------
//
// Configure ADC0 to use Timer3 overflows as conversion source, to
// generate an interrupt on conversion complete, and to use left-justified
// output mode.  Enables ADC end of conversion interrupt. Leaves ADC disabled.
//
void ADC0_Init (void)
{
   char SFRPAGE_SAVE = SFRPAGE;        // Save Current SFR page

   SFRPAGE = ADC0_PAGE;

   ADC0CN = 0x05;                      // ADC0 disabled; normal tracking
                                       // mode; ADC0 conversions are initiated
                                       // on overflow of Timer3; ADC0 data is
                                       // left-justified
   REF0CN = 0x07;                      // enable temp sensor, on-chip VREF,
                                       // and VREF output buffer
   AMX0SL = 0x0f;                      // Select TEMP sens as ADC mux output
   ADC0CF = (SYSCLK/2500000) << 3;     // ADC conversion clock = 2.5MHz
   ADC0CF |= 0x01;                     // PGA gain = 2

   EIE2 |= 0x02;                       // enable ADC interrupts

   SFRPAGE = SFRPAGE_SAVE;             // Restore SFR page
}

//-----------------------------------------------------------------------------
// Timer3_Init
//-----------------------------------------------------------------------------
//
// Configure Timer3 to auto-reload at interval specified by <counts> (no
// interrupt generated) using SYSCLK as its time base.
//
void Timer3_Init (int counts)
{
   char SFRPAGE_SAVE = SFRPAGE;        // Save Current SFR page

   SFRPAGE = TMR3_PAGE;

   TMR3CN = 0x00;                      // Stop Timer3; Clear TF3;
   TMR3CF = 0x08;                      // use SYSCLK as timebase

   RCAP3   = -counts;                  // Init reload values
   TMR3    = RCAP3;                    // set to reload immediately
   EIE2   &= ~0x01;                    // disable Timer3 interrupts
   TR3 = 1;                            // start Timer3

   SFRPAGE = SFRPAGE_SAVE;             // Restore SFR page
}

//-----------------------------------------------------------------------------
// Interrupt Service Routines
//-----------------------------------------------------------------------------

//-----------------------------------------------------------------------------
// ADC0_ISR
//-----------------------------------------------------------------------------
//
// ADC0 end-of-conversion ISR
// Here we take the ADC0 sample, add it to a running total <accumulator>, and
// decrement our local decimation counter <int_dec>.  When <int_dec> reaches
// zero, we post the decimated result in the global variable <result>.
//
void ADC0_ISR (void) interrupt 15
{
   static unsigned int_dec=INT_DEC;    // integrate/decimate counter
                                       // we post a new result when
                                       // int_dec = 0
   static long accumulator=0L;         // here's where we integrate the
                                       // ADC samples

   AD0INT = 0;                         // clear ADC conversion complete
                                       // indicator

   accumulator += ADC0;                // read ADC value and add to running
                                       // total
   int_dec--;                          // update decimation counter

   if (int_dec == 0) {                 // if zero, then post result
      int_dec = INT_DEC;               // reset counter
      result = accumulator >> 8;
      accumulator = 0L;                // reset accumulator
   }
}