Posted on November 30, 2015 at 12:54Hello
Im currently trying to read a incremental encoder via timer3 (channel3/4). Im working with a STM32F103RBTx.
The encoder is connected to PC8 and PC9.
If i connect the encoder to PC6 and PC7 (Tim3_CH1/2), then i can successfully read the encoder value. But since im going to use PC6/PC7 otherwise, im trying to do the same thing with Tim3_CH3/4. (Funny thing is, the encoder_counter can still be read on PC6/7 even if i configure GPIO PC8 and 9)
Is there something missing?
Here some code:
/* Encoder: Enable and set TIM3 general Interrupt */
NVIC_InitStructure.NVIC_IRQChannel = TIM3_IRQn;
NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0;
NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0;
NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
NVIC_Init(&NVIC_InitStructure);
RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOC, ENABLE);
RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM3, ENABLE);
RCC_APB2PeriphClockCmd(RCC_APB2Periph_AFIO, ENABLE);
/* GPIO Configuration */
#define PORT_TI GPIOC
#define GPIO_TI1 GPIO_Pin_8
#define GPIO_TI2 GPIO_Pin_9
/* Encoder: Configure PC8 and PC9 as input function */
GPIO_InitStructure.GPIO_Pin = GPIO_TI1 | GPIO_TI2;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IN_FLOATING;
GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
GPIO_Init(PORT_TI, &GPIO_InitStructure);
GPIO_PinRemapConfig(GPIO_FullRemap_TIM3, ENABLE); //Ref. Man. p. 178 (DocID13902 Rev 15)
void TIM_Configuration (void)
{
TIM_TimeBaseInitTypeDef TIM_TimeBaseStructure;
/* 32bit Timestamp: Configuration of Timer2 for Slave */
TIM_TimeBaseStructure.TIM_Prescaler = 0;
TIM_TimeBaseStructure.TIM_Period = 0xFFFF;
TIM_TimeBaseStructure.TIM_ClockDivision = TIM_CKD_DIV1;
TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;
TIM_TimeBaseInit(TIM2, &TIM_TimeBaseStructure);
// Select TIM1 Trigger Output as Trigger
TIM_SelectInputTrigger(TIM2, TIM_TS_ITR0);
// Slave Mode selection: Trigger on external Trigger
TIM_SelectSlaveMode(TIM2, TIM_SlaveMode_External1);
// Enable the TIM2 Master Slave Mode
TIM_SelectMasterSlaveMode(TIM2, TIM_MasterSlaveMode_Enable);
// TIM2 enable
TIM_Cmd(TIM2, ENABLE);
/* 32bit Timestamp: Configuration of Timer1 for Master */
TIM_TimeBaseStructure.TIM_Prescaler = 7199; // Prescaler = Teilerwert - 1
TIM_TimeBaseStructure.TIM_Period = 0xFFFF;
TIM_TimeBaseStructure.TIM_ClockDivision = TIM_CKD_DIV1;
TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;
TIM_TimeBaseInit(TIM1, &TIM_TimeBaseStructure);
// Master Mode selection: Output Trigger on Update (Overflow)
TIM_SelectOutputTrigger(TIM1, TIM_TRGOSource_Update);
// Select the Master Slave Mode: Output Trigger TRGO on TIM_TS_ITR0
TIM_SelectMasterSlaveMode(TIM1, TIM_MasterSlaveMode_Enable);
// Clear Counters
TIM_SetCounter (TIM1, 0);
TIM_SetCounter (TIM2, 0);
// TIM1 enable
TIM_Cmd(TIM1, ENABLE);
/* 32bit Encoder: Configuration of Timer3 in Encoder Mode */
TIM_TimeBaseStructure.TIM_Prescaler = 0;
TIM_TimeBaseStructure.TIM_Period = 0xFFFF;
TIM_TimeBaseStructure.TIM_ClockDivision = TIM_CKD_DIV1;
TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;
TIM_TimeBaseInit(TIM3, &TIM_TimeBaseStructure);
TIM_EncoderInterfaceConfig(TIM3, TIM_EncoderMode_TI12, TIM_ICPolarity_Rising, TIM_ICPolarity_Rising);
// Interrupt Flag löschen
TIM_ClearITPendingBit(TIM3, TIM_IT_Update);
// Enable Interrupt on update (under-/overflow of timer)
TIM_ITConfig(TIM3, TIM_IT_Update, ENABLE);
// TIM enable
TIM_Cmd(TIM3, ENABLE);
}
void TIM3_IRQHandler(void)
{
// Aktueller Zählerstand
static uint16_t counterValue;
// Lesen des aktuellen Zählerstands
counterValue = TIM_GetCounter(TIM3);
if(counterValue < 0x8000)
{
// Nach Overflow werden die oberen 2 Byte inkrementiert
TIM3CounterHighByte++;
} else
{
// Nach Underflow werden die oberen 2 Byte dekrementiert
TIM3CounterHighByte--;
}
/*****************************************************************************
* Beispiel zur Anpassung der Auflösung des Encoders auf 24bit.
*****************************************************************************/
/*if(counterValue < 0x8000)
{
TIM3CounterHighByte++;
TIM3CounterHighByte &= 0x00FF;
} else
{
TIM3CounterHighByte--;
TIM3CounterHighByte &= 0x00FF;
}*/
/* Clear TIM3 Trigger pending bit */
TIM_ClearITPendingBit(TIM3, TIM_IT_Update);
}
