Xmega Application Note | |||||
This file contains an example application that demonstrates the DAC driver. It shows how to set up the DAC in dual-channel mode with correct sample and refresh timing. The example outputs two triangle waves, phase shifted 180 degrees.
The sample and refresh timing settings are based on a CPU frequency of 2 MHz. Please refer to the module datasheet for more details on sample and refresh timing limits.
As this is a DAC example only, we do not use any Timer/counter to produce a specific waveform frequency. The code outputs the triangle wave with the highest frequency possible with this unoptimized C code.
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Definition in file dac_example.c.
#include "dac_driver.h"
Go to the source code of this file.
Functions | |
int | main (void) |
DAC example code. |
int main | ( | void | ) |
DAC example code.
This is an example code which output a triangle waveform on channel 0, and a 180 degree phase shift channel 1. The example code use a blocking while loop to ensure that the data register is empty before a new value is written.
Definition at line 68 of file dac_example.c.
References CH0, CH1, DAC_Channel_DataEmpty(), DAC_Channel_Write(), and DAC_DualChannel_Enable().
00069 { 00070 uint16_t angle; 00071 00072 /* Given 2 MHz CPU speed, this is configured to 2µs separation time and 00073 * 16µs refresh time. 00074 */ 00075 DAC_DualChannel_Enable( &DACA, 00076 DAC_REFSEL_AVCC_gc, 00077 false, 00078 DAC_CONINTVAL_4CLK_gc, 00079 DAC_REFRESH_32CLK_gc ); 00080 00081 /* Use a 12 bit variable to output two triangle waves, separated by 00082 * 180 degrees phase, as fast as possible. 00083 */ 00084 while (1) { 00085 for ( angle = 0; angle < 0x1000; ++angle ) { 00086 while ( DAC_Channel_DataEmpty( &DACA, CH0 ) == false ) { 00087 /* Blocking code waiting for empty register. */ 00088 } 00089 DAC_Channel_Write( &DACA, angle, CH0 ); 00090 while ( DAC_Channel_DataEmpty( &DACA, CH1 ) == false ) { 00091 /* Blocking code waiting for empty register. */ 00092 } 00093 DAC_Channel_Write( &DACA, 0xFFF - angle, CH1 ); 00094 } 00095 for ( angle = 0; angle < 0x1000; ++angle ) { 00096 while ( DAC_Channel_DataEmpty( &DACA, CH0 ) == false ) { 00097 /* Blocking code waiting for empty register. */ 00098 } 00099 DAC_Channel_Write( &DACA, 0xFFF - angle, CH0 ); 00100 while ( DAC_Channel_DataEmpty( &DACA, CH1 ) == false ) { 00101 /* Blocking code waiting for empty register. */ 00102 } 00103 DAC_Channel_Write( &DACA, angle, CH1 ); 00104 } 00105 } 00106 }
Generated on Wed May 14 16:11:05 2008 for AVR1301 Using the XMEGA DAC by ![]() |