Posted on February 01, 2016 at 11:16
Or the last:
Why? Any idea?
Thanks
Stuk
#!stm32 #!timer #!outputcompare
Hi, i'm trying to use timer2 to generate two output shifted by 90 degree, like an encoder emulator. The idea is using the period of the timer2 to set the frequency, and set two output compare ch2,ch3 to set the output.
This is the code i'm using to set the timers:
static
int
numPackets;
static
int
currentPackets;
void
setQuadraticOutputConfig(
long
frequency,
long
_numPackets,
long
direction)
{
numPackets = (_numPackets*2)-1;
currentPackets = 0;
double
tmp = 0;
unsigned
long
period = (TIMER_FREQ/(frequency*2)-1);
unsigned
long
pulseA = period/4;
unsigned
long
pulseB = pulseA*3;
TIM_ClockConfigTypeDef sClockSourceConfig;
TIM_MasterConfigTypeDef sMasterConfig;
TIM_OC_InitTypeDef sConfigOC;
htim2.Instance = TIM2;
htim2.Init.Prescaler = 0;
htim2.Init.CounterMode = TIM_COUNTERMODE_UP;
htim2.Init.Period = period;
htim2.Init.ClockDivision = TIM_CLOCKDIVISION_DIV1;
HAL_TIM_Base_DeInit(&htim2);
HAL_TIM_Base_Init(&htim2);
sClockSourceConfig.ClockSource = TIM_CLOCKSOURCE_INTERNAL;
HAL_TIM_ConfigClockSource(&htim2, &sClockSourceConfig);
HAL_TIM_OC_Init(&htim2);
sMasterConfig.MasterOutputTrigger = TIM_TRGO_UPDATE;
sMasterConfig.MasterSlaveMode = TIM_MASTERSLAVEMODE_DISABLE;
HAL_TIMEx_MasterConfigSynchronization(&htim2, &sMasterConfig);
sConfigOC.OCMode = TIM_OCMODE_TOGGLE;
if
(direction)
sConfigOC.Pulse = pulseA;
else
sConfigOC.Pulse = pulseB;
sConfigOC.OCPolarity = TIM_OCPOLARITY_LOW;
sConfigOC.OCFastMode = TIM_OCFAST_ENABLE;
HAL_TIM_OC_ConfigChannel(&htim2, &sConfigOC, TIM_CHANNEL_2);
if
(direction)
sConfigOC.Pulse = pulseB;
else
sConfigOC.Pulse = pulseA;
HAL_TIM_OC_ConfigChannel(&htim2, &sConfigOC, TIM_CHANNEL_3);
TIM2->CNT = 0;
//Force timer2 to 0
HAL_TIM_OC_Start_IT(&htim2, TIM_CHANNEL_2);
HAL_TIM_OC_Start_IT(&htim2, TIM_CHANNEL_3);
HAL_TIM_Base_Start_IT(&htim2);
}
void
HAL_TIM_PeriodElapsedCallback(TIM_HandleTypeDef *htim)
{
if
(htim == &htim2){
if
(currentPackets == numPackets)
{
HAL_TIM_OC_Stop(&htim2, TIM_CHANNEL_2);
HAL_TIM_OC_Stop(&htim2, TIM_CHANNEL_3);
HAL_TIM_Base_Stop(&htim2);
}
currentPackets++;
}
}
