Posted on September 06, 2017 at 22:27hi everyone,
I'm trying to generate a square wave / quadrature signal ( 2 square wave with 90 degrees offset). The board is a STM32F103C8
The goal of the project will be to send an exact number of pulse. Frequency will stay the same. I will have to be able to switch the direction of the signal such as a quadrature encoder.
Right now, I just want to have a clean quadrature signal. My code is not complicated at the moment and here are the 2 mains functions in order to initialize the timer:
void init_SW()
{
GPIO_InitTypeDef GPIO_InitStruct;
// Step 1: Initialize GPIO as input for rotary encoder
// PB7 (TIM4_CH2) (encoder pin A), PB6 (TIM4_CH1) (encoder pin B)
RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOB, ENABLE);
GPIO_InitStruct.GPIO_Pin = GPIO_Pin_7 | GPIO_Pin_6;
GPIO_InitStruct.GPIO_Mode = GPIO_Mode_AF_PP;
GPIO_InitStruct.GPIO_Speed = GPIO_Speed_2MHz;
GPIO_Init(GPIOB, &GPIO_InitStruct);
// Step 2: Setup TIM4 for encoder input
RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM4, ENABLE);
TIM_TimeBaseInitTypeDef TIM_TimeBaseStructure;
TIM_TimeBaseStructInit (&TIM_TimeBaseStructure);
TIM_TimeBaseStructure.TIM_Period = 3;
TIM_TimeBaseStructure.TIM_Prescaler = 0;
// TIM_Cmd(TIM4, ENABLE);
TIM_TimeBaseInit (TIM4, &TIM_TimeBaseStructure);
TIM4->CCER;
}
void timer_ccr_init (void)
{
TIM_OCInitTypeDef TIM_OCInitStructure;
/* always initialise local variables before use */
TIM_OCStructInit (&TIM_OCInitStructure);
/* Common settings for all channels */
TIM_OCInitStructure.TIM_OCMode = TIM_OCMode_Toggle;
TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable;
/* Channel1 */
TIM_OCInitStructure.TIM_Pulse = 0;
TIM_OC1Init (TIM4, &TIM_OCInitStructure);
/* Channel2 - 90 degres after*/
TIM_OCInitStructure.TIM_Pulse = 1;
TIM_OC2Init (TIM4, &TIM_OCInitStructure);
TIM4->CCER;
TIM_Cmd(TIM4, ENABLE);
}
Right now, my signal is absolutely not square. This is the first time I'm using a timer to generate a signal.
I tried to take what I needed from here
http://www.micromouseonline.com/2016/02/05/clock-pulses-with-variable-phase-stm32/
and adapt but without success right now
Thank you for your help
