Posted on June 28, 2012 at 17:48
STM32F4 TIMER 1 PWM1. Please can someone tell me how to enable channels 1, 2 and 3. Channel 4 is fine generating a PWM at 0..100% at 20Hz. I know channels 1..3 hardware is different - just can't figure out what to do to get the outputs enabled.
Thanks.
#include ''stm32f4xx.h'' //CMSIS Cortex-M4 Device Peripheral Access Layer Header File.
#include ''main.h''
uint16_t CCR1_Val = 30; //LED PWM range 0..100
uint16_t CCR2_Val = 40;
uint16_t CCR3_Val = 50;
uint16_t CCR4_Val = 60;
int main (void)
{
/*
At this stage the microcontroller clock setting is already configured by the
SystemInit() function called from startup file (startup_stm32f4xx.s). To reconfigure
the default setting of SystemInit() function, refer to system_stm32f4xx.c file.
*/
//enable peripheral clocks before attempting to initialise them
//for PWM based on Timer1 using GPIO on port E
RCC_APB2PeriphClockCmd(RCC_APB2Periph_TIM1, ENABLE);
RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOE, ENABLE);
//initialise the NVIC before configuring or enabling peripherals
NVIC_PriorityGroupConfig(NVIC_PriorityGroup_4); //4 bits for pre-emption priority 0 bits for subpriority
//initialise the GPIO and alternate functions to set up hardware
GPIO_Configuration_PWM();
//finally, initialise peripherals as required
Timer1_Configuration();
while(1); // Spin endlessly
}
void GPIO_Configuration_PWM(void)
{
GPIO_InitTypeDef GPIO_InitStructure;
/* GPIOE Configuration: TIM1 CH1 (PE9), TIM1 CH2 (PE11), TIM1 CH3 (PE13) and TIM1 CH4 (PE14) */
GPIO_InitStructure.GPIO_Pin = (GPIO_Pin_9 | GPIO_Pin_11 | GPIO_Pin_13 | GPIO_Pin_14);
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF;
GPIO_InitStructure.GPIO_Speed = GPIO_Speed_2MHz;
GPIO_InitStructure.GPIO_OType = GPIO_OType_PP;
GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_UP ;
GPIO_Init(GPIOE, &GPIO_InitStructure);
// Connect TIM1 pins to AF
GPIO_PinAFConfig(GPIOE, GPIO_PinSource9, GPIO_AF_TIM1);
GPIO_PinAFConfig(GPIOE, GPIO_PinSource11, GPIO_AF_TIM1);
GPIO_PinAFConfig(GPIOE, GPIO_PinSource13, GPIO_AF_TIM1);
GPIO_PinAFConfig(GPIOE, GPIO_PinSource14, GPIO_AF_TIM1);
}
void Timer1_Configuration(void)
{
//timer 1 is clocked by APB2 at 84MHz, prescale by 42000 to get 2kHz clock
//use a period of 100 cycles to get 0..100% granularity and 20Hz frequency
TIM_TimeBaseInitTypeDef TIM_TimeBaseStructure;
TIM_OCInitTypeDef TIM_OCInitStructure;
TIM_TimeBaseStructInit(&TIM_TimeBaseStructure);
TIM_TimeBaseStructure.TIM_Period = (100-1);
TIM_TimeBaseStructure.TIM_Prescaler = (42000-1);
TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;
TIM_TimeBaseInit(TIM1, &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(TIM1, &TIM_OCInitStructure);
TIM_OC1PreloadConfig(TIM1, TIM_OCPreload_Enable);
/* PWM1 Mode configuration: Channel2 */
TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable;
TIM_OCInitStructure.TIM_Pulse = CCR2_Val;
TIM_OC2Init(TIM1, &TIM_OCInitStructure);
TIM_OC2PreloadConfig(TIM1, TIM_OCPreload_Enable);
/* PWM1 Mode configuration: Channel3 */
TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable;
TIM_OCInitStructure.TIM_Pulse = CCR3_Val;
TIM_OC3Init(TIM1, &TIM_OCInitStructure);
TIM_OC3PreloadConfig(TIM1, TIM_OCPreload_Enable);
/* PWM1 Mode configuration: Channel4 */
TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable;
TIM_OCInitStructure.TIM_Pulse = CCR4_Val;
TIM_OC4Init(TIM1, &TIM_OCInitStructure);
TIM_OC4PreloadConfig(TIM1, TIM_OCPreload_Enable);
TIM_ARRPreloadConfig(TIM1, ENABLE);
//required for timers 1 or 8
TIM_CtrlPWMOutputs(TIM1, ENABLE);
/* TIM1 enable counter */
TIM_Cmd(TIM1, ENABLE);
}
