This seems to work fine (timer linkage used in my current firmware) but the Reference manual (Doc ID16188 Rev 5) suggests this internal trigger (ITR0) is not available in low & medium density devices?!
Can I rely on all future batches of the STM32F100V8T MCU allowing this timer linkage, or should I look to combine two different timers? (I am already using most other timers, and I hope I do not need to change anything!)
The STM32 cubeMx tool seems to show that TIM15 ITR0 is available and can be configured on the STM32F100V8Tx MCU - see attached screen grab.
I have some common code that is used to configure timer 2 and timer 15 to create linked microsecond and millisecond ticks. This initialisation code works fine, and links the timers as intended, despite the reference manual suggesting TIM15 ITR0 is not available.
/*Timer handles*/
static TIM_HandleTypeDef h_timUS;
static TIM_HandleTypeDef h_timMS;
bool initTimers(void)
{
bool success = TRUE;
TIM_MasterConfigTypeDef masterConfig;
TIM_OC_InitTypeDef outputCompare_Config;
TIM_SlaveConfigTypeDef slaveConfig;
timerClockFrequencyHz = US_COUNTER_CLK;
/* US_COUNTER - counts microseconds and resets at 1024 i.e. bits 1-10*/
h_timUS.Instance = TIM2;
h_timUS.Init.Prescaler = (US_COUNTER_CLK/1000000)-1; /*23, as US_COUNTER_CLK = 24MHz*/
h_timUS.Init.CounterMode = TIM_COUNTERMODE_UP;
h_timUS.Init.Period = 0x3FF; /*reset at 1023*/
h_timUS.Init.ClockDivision = TIM_CLOCKDIVISION_DIV1;
success &= (HAL_OK==HAL_TIM_OC_Init(&h_timUS));
/*Master config*/
masterConfig.MasterOutputTrigger = TIM_TRGO_OC1REF;
masterConfig.MasterSlaveMode = TIM_MASTERSLAVEMODE_ENABLE;
success &= (HAL_OK==HAL_TIMEx_MasterConfigSynchronization(&h_timUS, &masterConfig));
/*Output compare channel 1 config*/
outputCompare_Config.OCMode = TIM_OCMODE_PWM1;
outputCompare_Config.Pulse = 1;
outputCompare_Config.OCPolarity = TIM_OCPOLARITY_HIGH;
outputCompare_Config.OCFastMode = TIM_OCFAST_DISABLE;
success &= (HAL_OK==HAL_TIM_PWM_ConfigChannel(&h_timUS, &outputCompare_Config, TIM_CHANNEL_1));
/* MS_COUNTER - counts remaining bits (11-24)*/
h_timMS.Instance = TIM15;
h_timMS.Init.Prescaler = 0;
h_timMS.Init.CounterMode = TIM_COUNTERMODE_UP;
h_timMS.Init.Period = 0x3FFF;
h_timMS.Init.ClockDivision = TIM_CLOCKDIVISION_DIV1;
success &= (HAL_OK==HAL_TIM_Base_Init(&h_timMS));
/* Select the Input Triggers */
slaveConfig.SlaveMode = TIM_SLAVEMODE_EXTERNAL1;
slaveConfig.InputTrigger = TIM_TS_ITR0;
success &= (HAL_OK==HAL_TIM_SlaveConfigSynchronization(&h_timMS, &slaveConfig));
/* Initialise timer values to 0*/
__HAL_TIM_SET_COUNTER(&h_timUS,0);
__HAL_TIM_SET_COUNTER(&h_timMS,0);
/* Enable timers */
success &= (HAL_OK==HAL_TIM_Base_Start(&h_timMS));
success &= (HAL_OK==HAL_TIM_OC_Start_IT(&h_timUS, TIM_CHANNEL_1));
return success;
}Reference manual extracts (Doc ID16188 Rev 5 page 420);
