/** * @brief Configure TIM1 to to capture the internal clock source (LSI) * @param None * @retval None */ static void TIM1_Config(void) { TIM1_ICInit( TIM1_CHANNEL_1, TIM1_ICPOLARITY_FALLING, TIM1_ICSELECTION_DIRECTTI, TIM1_ICPSC_DIV8, 0x0); /* Enable TIM1 */ TIM1_Cmd(ENABLE); /* Clear CC1 Flag*/ TIM1_ClearFlag(TIM1_FLAG_CC1); /* wait a capture on CC1 */ while((TIM1->SR1 & TIM1_FLAG_CC1) != TIM1_FLAG_CC1); /* Get CCR1 value*/ ICValue1 = TIM1_GetCapture1(); TIM1_ClearFlag(TIM1_FLAG_CC1); /* wait a capture on cc1 */ while((TIM1->SR1 & TIM1_FLAG_CC1) != TIM1_FLAG_CC1); /* Get CCR1 value*/ ICValue2 = TIM1_GetCapture1(); TIM1_ClearFlag(TIM1_FLAG_CC1); }
/** * @brief Measure the LSI frequency using timer IC1 and update the calibration registers. * @par Parameters: * None * @retval * None * @par Required preconditions: * It is recommanded to use a timer clock frequency of at least 10MHz in order * to obtain a better in the LSI frequency measurement. */ u32 LSIMeasurment(void) { u32 lsi_freq_hz = 0x0; u32 fmaster = 0x0; u16 ICValue1 = 0x0; u16 ICValue2 = 0x0; /* Get master frequency */ fmaster = CLK_GetClockFreq(); /* Enable the LSI measurement: LSI clock connected to timer Input Capture 1 */ AWU->CSR |= AWU_CSR_MSR; #if defined (STM8S903) || defined (STM8S103) /* Measure the LSI frequency with TIMER Input Capture 1 */ /* Capture only every 8 events!!! */ /* Enable capture of TI1 */ TIM1_ICInit(TIM1_CHANNEL_1, TIM1_ICPOLARITY_RISING, TIM1_ICSELECTION_DIRECTTI, TIM1_ICPSC_DIV8, 0); /* Enable TIM1 */ TIM1_Cmd(ENABLE); /* wait a capture on cc1 */ while((TIM1->SR1 & TIM1_FLAG_CC1) != TIM1_FLAG_CC1); /* Get CCR1 value*/ ICValue1 = TIM1_GetCapture1(); TIM1_ClearFlag(TIM1_FLAG_CC1); /* wait a capture on cc1 */ while((TIM1->SR1 & TIM1_FLAG_CC1) != TIM1_FLAG_CC1); /* Get CCR1 value*/ ICValue2 = TIM1_GetCapture1(); TIM1_ClearFlag(TIM1_FLAG_CC1); /* Disable IC1 input capture */ TIM1->CCER1 &= (u8)(~TIM1_CCER1_CC1E); /* Disable timer2 */ TIM1_Cmd(DISABLE); #else /* Measure the LSI frequency with TIMER Input Capture 1 */ /* Capture only every 8 events!!! */ /* Enable capture of TI1 */ TIM3_ICInit(TIM3_CHANNEL_1, TIM3_ICPOLARITY_RISING, TIM3_ICSELECTION_DIRECTTI, TIM3_ICPSC_DIV8, 0); /* Enable TIM3 */ TIM3_Cmd(ENABLE); /* wait a capture on cc1 */ while ((TIM3->SR1 & TIM3_FLAG_CC1) != TIM3_FLAG_CC1); /* Get CCR1 value*/ ICValue1 = TIM3_GetCapture1(); TIM3_ClearFlag(TIM3_FLAG_CC1); /* wait a capture on cc1 */ while ((TIM3->SR1 & TIM3_FLAG_CC1) != TIM3_FLAG_CC1); /* Get CCR1 value*/ ICValue2 = TIM3_GetCapture1(); TIM3_ClearFlag(TIM3_FLAG_CC1); /* Disable IC1 input capture */ TIM3->CCER1 &= (u8)(~TIM3_CCER1_CC1E); /* Disable timer3 */ TIM3_Cmd(DISABLE); #endif /* Compute LSI clock frequency */ lsi_freq_hz = (8 * fmaster) / (ICValue2 - ICValue1); /* Disable the LSI measurement: LSI clock disconnected from timer Input Capture 1 */ AWU->CSR &= (u8)(~AWU_CSR_MSR); return (lsi_freq_hz); }