main.cpp

00001 #include "mbed.h"
00002 #include "analogout_api.h"
00003 #include "mbed-os/targets/TARGET_STM/TARGET_STM32L4/device/stm32l4xx_ll_dac.h"
00004 
00005 #if !DEVICE_ANALOGOUT
00006 #error You cannot use this example as the AnalogOut is not supported on this device.
00007 #else
00008 AnalogOut sinOut( PA_4 ); // channel 1
00009 #endif
00010 
00011 #define PI        (3.141592653589793238462f)
00012 #define AMPLITUDE (0.3)    // x * 3.3V
00013 #define PHASE     (PI * 1.0f) // 2*pi is one period
00014 #define OFFSET    (0.5f)
00015 
00016 // Configuration for sinewave output
00017 /* #define BUFFER_SIZE (540U) */
00018 #define BUFFER_SIZE (1024U)
00019 unsigned int buffer[BUFFER_SIZE];
00020 
00021 void calculate_sinewave( void );
00022 
00023 int main()
00024         {
00025         calculate_sinewave();
00026 
00027         const int stepBuffN = 12;
00028         float stepBuff[stepBuffN] = {};
00029         AnalogOut stepOut( PA_5 );
00030 
00031         for( int i = 0; i < stepBuffN; i += 3 )
00032                 {
00033                 stepBuff[i] = 3.0f / 3.3f;
00034                 stepBuff[i + 1] = 2.0f / 3.3f;
00035                 stepBuff[i + 2] = 1.0f / 3.3f;
00036                 };
00037 
00038         stepOut = stepBuff[0];
00039 
00040         core_util_critical_section_enter();
00041 
00042         HAL_SuspendTick();
00043 
00044         core_util_critical_section_exit();
00045 
00046         dac_t* obj = &sinOut._dac;
00047 
00048         DAC_HandleTypeDef dacHandle = obj->handle;
00049 
00050         uint32_t dacChannel = obj->channel;
00051 
00052         for( unsigned int i = 0; i < BUFFER_SIZE; i++ )
00053                 {
00054                 buffer[i] *= 0xFFF;
00055                 }
00056 
00057         while( 1 )
00058                 {
00059                 // sinewave output
00060 
00061                 for( int i = 0; i < BUFFER_SIZE; ++i )
00062                         {
00063                         HAL_DAC_SetValue( &dacHandle, dacChannel, DAC_ALIGN_12B_R, buffer[i] );
00064                         HAL_DAC_Start( &dacHandle, dacChannel );
00065                         }
00066                 }
00067         }
00068 
00069 // Create the sinewave buffer
00070 void calculate_sinewave( void )
00071         {
00072         for( unsigned int i = 0; i < BUFFER_SIZE; i++ )
00073                 {
00074                 float rads = 2.0f * ( PI * i ) / ( ( float )BUFFER_SIZE ); // Convert degree in radian
00075                 buffer[i] = ( unsigned int )( 0xFFF * AMPLITUDE * cos( rads + PHASE ) + 0xFFF * OFFSET );
00076                 }
00077         }