adc0_poll1.c

c8051f020开发板的所有参考程序

//-----------------------------------------------------------------------------
// ADC0_Poll1.c
//-----------------------------------------------------------------------------
// Copyright 2001 Cygnal Integrated Products, Inc.
//
// AUTH: BW
// DATE: 18 AUG 01
//
// This program demonstrates operation of ADC0 in polled mode.  The ADC0 is
// configured to use writes to AD0BUSY as its start of conversion source and
// to measure the output of the on-chip temperature sensor.  The temperature
// sensor output is converted to degrees Celsius and is transmitted out UART0.
// Assumes an 22.1184MHz crystal is attached between XTAL1 and XTAL2.
// 
// The system clock frequency is stored in a global constant SYSCLK.  The
// target UART baud rate is stored in a global constant BAUDRATE.
//
// Target: C8051F02x
// Tool chain: KEIL C51 6.03 / KEIL EVAL C51
//

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

#include <c8051f020.h>                 // SFR declarations
#include <stdio.h>

//-----------------------------------------------------------------------------
// 16-bit SFR Definitions for 'F02x
//-----------------------------------------------------------------------------

sfr16 DP       = 0x82;                 // data pointer
sfr16 TMR3RL   = 0x92;                 // Timer3 reload value
sfr16 TMR3     = 0x94;                 // Timer3 counter
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 T2       = 0xcc;                 // Timer2
sfr16 RCAP4    = 0xe4;                 // Timer4 capture/reload
sfr16 T4       = 0xf4;                 // Timer4
sfr16 DAC0     = 0xd2;                 // DAC0 data
sfr16 DAC1     = 0xd5;                 // DAC1 data

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

#define SYSCLK       22118400          // SYSCLK frequency in Hz
#define BAUDRATE     9600              // Baud rate of UART in bps

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 UART0_Init (void);
void ADC0_Init (void);

//-----------------------------------------------------------------------------
// Global VARIABLES
//-----------------------------------------------------------------------------

//-----------------------------------------------------------------------------
// 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
   UART0_Init ();                      // initialize UART0

   ADC0_Init ();                       // init and enable ADC

   // *** check difference in tracking modes ***

   while (1) {
      AD0INT = 0;                      // clear conversion complete indicator
      AD0BUSY = 1;                     // initiate conversion
      while (AD0INT == 0);             // wait for conversion complete
      temperature = ADC0;              // read ADC0 data

      // calculate temperature in hundredths of a degree
      temperature = temperature - 41380;
      temperature = (temperature * 100L) / 156;
      temp_int = temperature / 100;
      temp_frac = temperature - (temp_int * 100);
      printf ("Temperature is %+02d.%02d\n", temp_int, temp_frac);
   }
}

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

//-----------------------------------------------------------------------------
// SYSCLK_Init
//-----------------------------------------------------------------------------
//
// This routine initializes the system clock to use an 22.1184MHz crystal
// as its clock source.
//
void SYSCLK_Init (void)
{
   int i;                              // delay counter

   OSCXCN = 0x67;                      // start external oscillator with
                                       // 22.1184MHz crystal

   for (i=0; i < 256; i++) ;           // XTLVLD blanking interval (>1ms)

   while (!(OSCXCN & 0x80)) ;          // Wait for crystal osc. to settle

   OSCICN = 0x88;                      // select external oscillator as SYSCLK
                                       // source and enable missing clock
                                       // detector
}

//-----------------------------------------------------------------------------
// PORT_Init
//-----------------------------------------------------------------------------
//
// Configure the Crossbar and GPIO ports
//
void PORT_Init (void)
{
   XBR0    = 0x04;                     // Enable UART0
   XBR1    = 0x00;
   XBR2    = 0x40;                     // Enable crossbar and weak pull-ups
   P0MDOUT |= 0x01;                    // enable TX0 as a push-pull output
   P1MDOUT |= 0x40;                    // enable P1.6 (LED) as push-pull output
}

//-----------------------------------------------------------------------------
// UART0_Init
//-----------------------------------------------------------------------------
//
// Configure the UART0 using Timer1, for <baudrate> and 8-N-1.
//
void UART0_Init (void)
{
   SCON0   = 0x50;                     // SCON0: mode 1, 8-bit UART, enable RX
   TMOD    = 0x20;                     // TMOD: timer 1, mode 2, 8-bit reload
   TH1    = -(SYSCLK/BAUDRATE/16);     // set Timer1 reload value for baudrate
   TR1    = 1;                         // start Timer1
   CKCON |= 0x10;                      // Timer1 uses SYSCLK as time base
   PCON  |= 0x80;                      // SMOD00 = 1
   TI0    = 1;                         // Indicate TX0 ready
}

//-----------------------------------------------------------------------------
// ADC0_Init
//-----------------------------------------------------------------------------
//
// Configure ADC0 to use AD0BUSY as conversion source, to use left-justified
// output mode, to use normal tracking mode, and to measure the output of 
// the on-chip temperature sensor.  Disables ADC0 end of conversion interrupt
// and ADC0 window compare interrupt.
//
void ADC0_Init (void)
{
   ADC0CN = 0x81;                      // ADC0 enabled; normal tracking
                                       // mode; ADC0 conversions are initiated 
                                       // on write to AD0BUSY; 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;                      // disable ADC0 EOC interrupt
   EIE1 &= ~0x04;                      // disable ADC0 window compare interrupt
}