//-----------------------------------------------------------------------------
// F02x_DACs_SineCosine.c
//-----------------------------------------------------------------------------
// Copyright 2006 Silicon Laboratories, Inc.
// http://www.silabs.com
//
// Program Description:
//
// This program outputs sine and cosine waveforms using the hardware DACs
// on the C8051F020 microcontroller. The waveforms are output on pins DAC0
// and DAC1.
//
// The output of the DAC is updated upon a Timer4 interrupt. The Timer4 ISR
// then calculates the output of the DACs for the next interrupt.
//
// The frequency of the output waveforms is set by the #define <FREQUENCY>.
//
//
// How To Test:
//
// 1) Download the code to an C8051F020 Development Board
// 2) Ensure that pins 1 and 2 on the J22 header on the development board
// are shorted together. This connects VREF to decoupling capacitors.
// 3) Connect two oscillscope probes to pins DAC0 and DAC1. These pins are
// available on both the J11 (pins 3 and 4 respectively) and J20 headers
// (pin 3 and 4 respectively).
// 4) Confirm that there are two waveforms with the output of DAC1 leading
// the output DAC0 by 90 degrees. The frequency of both waveforms should
// be close to frequency defined by <FREQUENCY>
//
// FID: 02X000014
// Target: C8051F02x
// Tool chain: Keil C51 7.50 / Keil EVAL C51
// Silicon Laboratories IDE version 2.71
// Command Line: Default
//
// Release 1.0
// -Initial Revision (GP)
// -10 JUL 2006
//
//-----------------------------------------------------------------------------
// Includes
//-----------------------------------------------------------------------------
#include <c8051f020.h> // SFR declarations
//-----------------------------------------------------------------------------
// 16-bit SFR Definitions for 'F02x
//-----------------------------------------------------------------------------
sfr16 RCAP4 = 0xE4; // Timer4 capture/reload
sfr16 TMR4 = 0xF4; // Timer4
sfr16 DAC0 = 0xd2; // DAC0 data
sfr16 DAC1 = 0xd5; // DAC1 data
//-----------------------------------------------------------------------------
// Global Constants
//-----------------------------------------------------------------------------
#define SYSCLK 22118400 // Internal oscillator frequency in Hz
#define SAMPLE_RATE_DAC 100000L // DAC sampling rate in Hz
#define PHASE_PRECISION 65536 // range of phase accumulator
#define FREQUENCY 1000 // Frequency of output waveform in Hz
// <PHASE_ADD> is the change in phase between DAC samples; It is used in
// the set_DACs routine.
unsigned int PHASE_ADD = FREQUENCY * PHASE_PRECISION / SAMPLE_RATE_DAC;
int code SINE_TABLE[256] = {
0x0000, 0x0324, 0x0647, 0x096a, 0x0c8b, 0x0fab, 0x12c8, 0x15e2,
0x18f8, 0x1c0b, 0x1f19, 0x2223, 0x2528, 0x2826, 0x2b1f, 0x2e11,
0x30fb, 0x33de, 0x36ba, 0x398c, 0x3c56, 0x3f17, 0x41ce, 0x447a,
0x471c, 0x49b4, 0x4c3f, 0x4ebf, 0x5133, 0x539b, 0x55f5, 0x5842,
0x5a82, 0x5cb4, 0x5ed7, 0x60ec, 0x62f2, 0x64e8, 0x66cf, 0x68a6,
0x6a6d, 0x6c24, 0x6dca, 0x6f5f, 0x70e2, 0x7255, 0x73b5, 0x7504,
0x7641, 0x776c, 0x7884, 0x798a, 0x7a7d, 0x7b5d, 0x7c29, 0x7ce3,
0x7d8a, 0x7e1d, 0x7e9d, 0x7f09, 0x7f62, 0x7fa7, 0x7fd8, 0x7ff6,
0x7fff, 0x7ff6, 0x7fd8, 0x7fa7, 0x7f62, 0x7f09, 0x7e9d, 0x7e1d,
0x7d8a, 0x7ce3, 0x7c29, 0x7b5d, 0x7a7d, 0x798a, 0x7884, 0x776c,
0x7641, 0x7504, 0x73b5, 0x7255, 0x70e2, 0x6f5f, 0x6dca, 0x6c24,
0x6a6d, 0x68a6, 0x66cf, 0x64e8, 0x62f2, 0x60ec, 0x5ed7, 0x5cb4,
0x5a82, 0x5842, 0x55f5, 0x539b, 0x5133, 0x4ebf, 0x4c3f, 0x49b4,
0x471c, 0x447a, 0x41ce, 0x3f17, 0x3c56, 0x398c, 0x36ba, 0x33de,
0x30fb, 0x2e11, 0x2b1f, 0x2826, 0x2528, 0x2223, 0x1f19, 0x1c0b,
0x18f8, 0x15e2, 0x12c8, 0x0fab, 0x0c8b, 0x096a, 0x0647, 0x0324,
0x0000, 0xfcdc, 0xf9b9, 0xf696, 0xf375, 0xf055, 0xed38, 0xea1e,
0xe708, 0xe3f5, 0xe0e7, 0xdddd, 0xdad8, 0xd7da, 0xd4e1, 0xd1ef,
0xcf05, 0xcc22, 0xc946, 0xc674, 0xc3aa, 0xc0e9, 0xbe32, 0xbb86,
0xb8e4, 0xb64c, 0xb3c1, 0xb141, 0xaecd, 0xac65, 0xaa0b, 0xa7be,
0xa57e, 0xa34c, 0xa129, 0x9f14, 0x9d0e, 0x9b18, 0x9931, 0x975a,
0x9593, 0x93dc, 0x9236, 0x90a1, 0x8f1e, 0x8dab, 0x8c4b, 0x8afc,
0x89bf, 0x8894, 0x877c, 0x8676, 0x8583, 0x84a3, 0x83d7, 0x831d,
0x8276, 0x81e3, 0x8163, 0x80f7, 0x809e, 0x8059, 0x8028, 0x800a,
0x8000, 0x800a, 0x8028, 0x8059, 0x809e, 0x80f7, 0x8163, 0x81e3,
0x8276, 0x831d, 0x83d7, 0x84a3, 0x8583, 0x8676, 0x877c, 0x8894,
0x89bf, 0x8afc, 0x8c4b, 0x8dab, 0x8f1e, 0x90a1, 0x9236, 0x93dc,
0x9593, 0x975a, 0x9931, 0x9b18, 0x9d0e, 0x9f14, 0xa129, 0xa34c,
0xa57e, 0xa7be, 0xaa0b, 0xac65, 0xaecd, 0xb141, 0xb3c1, 0xb64c,
0xb8e4, 0xbb86, 0xbe32, 0xc0e9, 0xc3aa, 0xc674, 0xc946, 0xcc22,
0xcf05, 0xd1ef, 0xd4e1, 0xd7da, 0xdad8, 0xdddd, 0xe0e7, 0xe3f5,
0xe708, 0xea1e, 0xed38, 0xf055, 0xf375, 0xf696, 0xf9b9, 0xfcdc,
};
//-----------------------------------------------------------------------------
// Function Prototypes
//-----------------------------------------------------------------------------
void main(void);
void OSCILLATOR_Init(void);
void DAC0_Init (void);
void DAC1_Init (void);
void TIMER4_Init(int counts);
void Set_DACs(void);
//-----------------------------------------------------------------------------
// MAIN Routine
//-----------------------------------------------------------------------------
void main (void)
{
WDTCN = 0xde; // Disable watchdog timer
WDTCN = 0xad;
OSCILLATOR_Init (); // Initialize oscillator
DAC0_Init (); // Initialize DAC0
DAC1_Init (); // Initialize DAC1
TIMER4_Init(SYSCLK/SAMPLE_RATE_DAC);// Initialize Timer4 to overflow
// <SAMPLE_RATE_DAC> times per
// second
EA = 1; // Enable global interrupts
while(1);
}
//-----------------------------------------------------------------------------
// Interrupt Service Routines
//-----------------------------------------------------------------------------
//-----------------------------------------------------------------------------
// TIMER4_ISR -- Wave Generator
//-----------------------------------------------------------------------------
//
// This ISR is called on Timer4 overflows. Timer4 is set to auto-reload mode
// and is used to schedule the DAC output sample rate in this example.
// Note that the value that is written to DAC1 during this ISR call is
// actually transferred to DAC1 at the next Timer4 overflow.
//
//-----------------------------------------------------------------------------
void TIMER4_ISR (void) interrupt 16
{
T4CON &= ~0x80; // Clear Timer4 overflow flag
Set_DACs();
}
//-----------------------------------------------------------------------------
// Initialization Routines
//-----------------------------------------------------------------------------
//-----------------------------------------------------------------------------
// OSCILLATOR_Init
//-----------------------------------------------------------------------------
//
// Return Value : None
// Parameters : None
//
// This routine initializes the system clock to use an 22.1184MHz crystal
// as its clock source.
//
//-----------------------------------------------------------------------------
void OSCILLATOR_Init (void)
{
int i; // Delay counter
OSCXCN = 0x67; // Start external oscillator with
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