Posted on May 17, 2011 at 13:56I see exactly what you are talking about in Figure 100. This basically means that there is a 'daisy chain' of configuration that has to be made in order to capture the transitions on TIM4_CH4. It is the following:
(1) TIM4_CH3
(2) TI3
(3) Input Filter/Edge Detector
(4) IC3
(5) Prescalar
(6) IC3PS
(7) Capture/Compare 4 Register
The configuration for making IC3 = TI3 is set by ''TIM_ICInitStructure.TIM_ICSelection = TIM_ICSelection_DirectTI;''.
For some reason when I configure TIM4_CH3 (TI3) to be selected as IC3 I cannot get my firmware to generate an interrupt and call ''TIM4_IRQHandler()''. I am using Keil RL-RTX and the library provided by Keil in ''C:\Keil\ARM\RV31\LIB\ST\STM32F10x'', where the NVIC is configured for TIM4_IRQChannel (=0x1F in Keil Library).
Is there anyway to troubleshoot why timer 4 is not generating an interrupt that calls the TIM4_IRQHandler() function?
The code modification that I have made is the following:
void InitializeInputCapture(void)
{
TIM_ICInitTypeDef TIM_ICInitStructure;
GPIO_InitTypeDef GPIO_InitStructure;
NVIC_InitTypeDef NVIC_InitStructure;
// RCC Configuration -------------------------------------------------------
// TIM3 clock enable
RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM4, ENABLE);
// GPIOA and GPIOB clock enable
RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOB, ENABLE);
// Configure the Nested Interrupt Vector -----------------------------------
// Enable the TIM3 global Interrupt
NVIC_InitStructure.NVIC_IRQChannel = TIM4_IRQChannel;
NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0;
NVIC_InitStructure.NVIC_IRQChannelSubPriority = 1;
NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
NVIC_Init(&NVIC_InitStructure);
// Input Capture Pin Configuration -----------------------------------------
GPIO_InitStructure.GPIO_Pin = GPIO_Pin_8;
//GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IN_FLOATING;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IPU;
GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
GPIO_Init(GPIOB, &GPIO_InitStructure);
// Input Capture Configuration ---------------------------------------------
TIM_ICInitStructure.TIM_Channel = TIM_Channel_3;
TIM_ICInitStructure.TIM_ICPolarity = TIM_ICPolarity_Rising;
TIM_ICInitStructure.TIM_ICSelection = TIM_ICSelection_DirectTI;
TIM_ICInitStructure.TIM_ICPrescaler = TIM_ICPSC_DIV8;
TIM_ICInitStructure.TIM_ICFilter = 0x0;
TIM_ICInit(TIM4, &TIM_ICInitStructure);
// TIM enable counter
TIM_Cmd(TIM4, ENABLE);
// Enable the CC2 Interrupt Request
TIM_ITConfig(TIM4, TIM_IT_CC3, ENABLE);
}
