![]() I tried running your code on my Arduino Zero and it didn't work for me. This will cause the timer to overflow every second. we can calculate CC0 for a timer frequency of 1Hz.ĬC0 = (48MHz / 1024) - 1 = 46874 = 0xB71A (hex) Timer frequency = generic clock frequency / (N * (CC0 + 1)) Therefore the timer's being clocked at 46.875kHz. I've set the generic clock 4 (GCLK4) to 48MHz and the timer prescaler to 1024. In this mode the timer counts up to the value in the CC0 register before overflowing and resetting the timer back to 0. The code puts timer TC4 into match frequency (MFRQ) mode. REG_TC4_INTFLAG = TC_INTFLAG_OVF // Clear the OVF interrupt flag Put your timer overflow (OVF) code here: Void TC4_Handler() // Interrupt Service Routine (ISR) for timer TC4 TC_CTRLA_WAVEGEN_MFRQ | // Put the timer TC4 into match frequency (MFRQ) mode REG_TC4_INTENCLR = TC_INTENCLR_OVF // Disable TC4 interrupts REG_TC4_INTENSET = TC_INTENSET_OVF // Enable TC4 interrupts REG_TC4_INTFLAG |= TC_INTFLAG_OVF // Clear the interrupt flags NVIC_EnableIRQ(TC4_IRQn) // Connect TC4 to Nested Vector Interrupt Controller (NVIC) NVIC_SetPriority(TC4_IRQn, 0) // Set the Nested Vector Interrupt Controller (NVIC) priority for TC4 to 0 (highest) While (TC4->) // Wait for synchronization REG_TC4_COUNT16_CC0 = 0xB71A // Set the TC4 CC0 register as the TOP value in match frequency mode GCLK_CLKCTRL_ID_TC4_TC5 // Feed the GCLK4 to TC4 and TC5 REG_GCLK_CLKCTRL = GCLK_CLKCTRL_CLKEN | // Enable GCLK4 to TC4 and TC5 GCLK_GENCTRL_SRC_DFLL48M | // Set the 48MHz clock source REG_GCLK_GENCTRL = GCLK_GENCTRL_IDC | // Set the duty cycle to 50/50 HIGH/LOW While (GCLK->) // Wait for synchronization GCLK_GENDIV_ID(4) // Select Generic Clock (GCLK) 4 REG_GCLK_GENDIV = GCLK_GENDIV_DIV(1) | // Divide the 48MHz clock source by divisor 1: 48MHz/1=48MHz Set up the generic clock (GCLK4) used to clock timers The following code calls the TC4_Handler() function every second: // Set timer TC4 to call the TC4_Handler every second TC->0 = 1 // writing a one clears the flag ovf flag ![]() put your main code here, to run repeatedly: TC->INTENSET.reg = 0 // disable all interrupts TC->PER.reg = 0xFF // Set counter Top using the PER register but the 16/32 bit timer counts allway to max TC->CTRLA.reg |= TC_CTRLA_PRESCALER_DIV256 // Set perscaler TC->CTRLA.reg |= TC_CTRLA_WAVEGEN_NFRQ // Set TC as normal Normal Frq TC->CTRLA.reg |= TC_CTRLA_MODE_COUNT16 // Set Timer counter Mode to 16 bits TC->CTRLA.reg &= ~TC_CTRLA_ENABLE // Disable TC TcCount16* TC = (TcCount16*) TC3 // get timer struct The type cast must fit with the selected timer mode REG_GCLK_CLKCTRL = (uint16_t) (GCLK_CLKCTRL_CLKEN | GCLK_CLKCTRL_GEN_GCLK0 | 0x1B) How to generate an interrupt at every one seconds using this. I read the timer function in SAMD21 datasheet and on the internet i found the following example code which generates interrupt on specific time. I am having problem of setting timer interrupt frequency in M0 board.
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