void vDebugInit(int exampleNum) {
vUSART2_Init();
vDebugInitQueue();
xTaskCreate((pdTASK_CODE)vDebugTask, (const signed char * const)"DEBUG", (unsigned short)configMINIMAL_STACK_SIZE, NULL, (unsigned portBASE_TYPE)mainDEBUG_TASK_PRIORITY, (xTaskHandle)NULL);
// Clear the screen.
vDebugPrintf("\e[2J\e[H");
vDebugPrintf("Example: %d\r\n",exampleNum);
vDebugPrintf("System Core Clock is running at: %dMHz\r\n",SystemCoreClock/1000000);
}
// ----------------------------------------------------------------------------
void HwInit( void ) {
SystemCoreClockUpdate( );
// Make sure SysTick is running at a 1ms rate.
if ( SysTick_Config( SystemCoreClock / 1000 ) ) {
/* Capture error */
while ( 1 );
}
// SysTick_CLKSourceConfig( SysTick_CLKSource_HCLK_Div8 );
/* Initialize Leds mounted on STM32F4-Discovery board */
STM_EVAL_LEDInit(LED4);
STM_EVAL_LEDInit(LED3);
STM_EVAL_LEDInit(LED5);
STM_EVAL_LEDInit(LED6);
/* Turn on LED4 and LED5 */
STM_EVAL_LEDOn(LED4);
STM_EVAL_LEDOn(LED5);
/* TIM Configuration */
TIM3_Config();
TIM4_Config();
/* -----------------------------------------------------------------------
TIM3 Configuration: generate 4 PWM signals with 4 different duty cycles.
In this example TIM3 input clock (TIM3CLK) is set to 2 * APB1 clock (PCLK1),
since APB1 prescaler is different from 1.
TIM3CLK = 2 * PCLK1
PCLK1 = HCLK / 4
=> TIM3CLK = HCLK / 2 = SystemCoreClock /2
To get TIM3 counter clock at 28 MHz, the prescaler is computed as follows:
Prescaler = (TIM3CLK / TIM3 counter clock) - 1
Prescaler = ((SystemCoreClock /2) /28 MHz) - 1
To get TIM3 output clock at 30 KHz, the period (ARR)) is computed as follows:
ARR = (TIM3 counter clock / TIM3 output clock) - 1
= 665
TIM3 Channel1 duty cycle = (TIM3_CCR1/ TIM3_ARR)* 100 = 50%
TIM3 Channel2 duty cycle = (TIM3_CCR2/ TIM3_ARR)* 100 = 37.5%
TIM3 Channel3 duty cycle = (TIM3_CCR3/ TIM3_ARR)* 100 = 25%
TIM3 Channel4 duty cycle = (TIM3_CCR4/ TIM3_ARR)* 100 = 12.5%
Note:
SystemCoreClock variable holds HCLK frequency and is defined in system_stm32f4xx.c file.
Each time the core clock (HCLK) changes, user had to call SystemCoreClockUpdate()
function to update SystemCoreClock variable value. Otherwise, any configuration
based on this variable will be incorrect.
----------------------------------------------------------------------- */
/* Compute the prescaler value */
PrescalerValue = (uint16_t) ((SystemCoreClock /2) / 28000000) - 1;
/* Time base configuration */
TIM_TimeBaseStructure.TIM_Period = 665;
TIM_TimeBaseStructure.TIM_Prescaler = PrescalerValue;
TIM_TimeBaseStructure.TIM_ClockDivision = 0;
TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;
TIM_TimeBaseInit( TIM3, &TIM_TimeBaseStructure );
TIM_TimeBaseInit( TIM4, &TIM_TimeBaseStructure );
/* PWM1 Mode configuration: Channel1 */
TIM_OCInitStructure.TIM_OCMode = TIM_OCMode_PWM1;
TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable;
TIM_OCInitStructure.TIM_Pulse = CCR1_Val;
TIM_OCInitStructure.TIM_OCPolarity = TIM_OCPolarity_High;
TIM_OC1Init( TIM3, &TIM_OCInitStructure );
TIM_OC1Init( TIM4, &TIM_OCInitStructure );
TIM_OC1PreloadConfig( TIM3, TIM_OCPreload_Enable );
TIM_OC1PreloadConfig( TIM4, TIM_OCPreload_Enable );
/* PWM1 Mode configuration: Channel2 */
TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable;
TIM_OCInitStructure.TIM_Pulse = CCR2_Val;
TIM_OC2Init( TIM3, &TIM_OCInitStructure );
TIM_OC2Init( TIM4, &TIM_OCInitStructure );
TIM_OC2PreloadConfig( TIM3, TIM_OCPreload_Enable );
TIM_OC2PreloadConfig( TIM4, TIM_OCPreload_Enable );
/* PWM1 Mode configuration: Channel3 */
TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable;
TIM_OCInitStructure.TIM_Pulse = CCR3_Val;
TIM_OC3Init( TIM3, &TIM_OCInitStructure );
TIM_OC3Init( TIM4, &TIM_OCInitStructure );
TIM_OC3PreloadConfig( TIM3, TIM_OCPreload_Enable );
TIM_OC3PreloadConfig( TIM4, TIM_OCPreload_Enable );
/* PWM1 Mode configuration: Channel4 */
TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable;
TIM_OCInitStructure.TIM_Pulse = CCR4_Val;
TIM_OC4Init( TIM3, &TIM_OCInitStructure );
TIM_OC4Init( TIM4, &TIM_OCInitStructure );
TIM_OC4PreloadConfig( TIM3, TIM_OCPreload_Enable );
TIM_OC4PreloadConfig( TIM4, TIM_OCPreload_Enable );
TIM_ARRPreloadConfig( TIM3, ENABLE );
TIM_ARRPreloadConfig( TIM4, ENABLE );
/* TIM3 enable counter */
TIM_Cmd( TIM3, ENABLE );
TIM_Cmd( TIM4, ENABLE );
vUSART2_Init(); // Start up UART2
}
