49 lines
980 B
C++
49 lines
980 B
C++
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#include "mbed.h"
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volatile unsigned int ticks = 0;
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DigitalOut led(LED_BLUE);
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extern "C" void lptmr_isr(void) {
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// write 1 to TCF to clear the LPT timer compare flag
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LPTMR0->CSR |= LPTMR_CSR_TCF_MASK;
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ticks++;
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}
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int main() {
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/* Clock the timer */
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SIM->SCGC5 |= SIM_SCGC5_LPTMR_MASK;
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/* Reset */
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LPTMR0->CSR = 0;
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/* Compare value */
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LPTMR0->CMR = 1000;
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/* Enable interrupt */
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LPTMR0->CSR |= LPTMR_CSR_TIE_MASK;
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/* Set interrupt handler */
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NVIC_SetVector(LPTimer_IRQn, (uint32_t)lptmr_isr);
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NVIC_EnableIRQ(LPTimer_IRQn);
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/* select LPO for RTC and LPTMR */
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LPTMR0->PSR = LPTMR_PSR_PCS(3); // ERCLK32K -> 8MHz
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LPTMR0->PSR |= LPTMR_PSR_PRESCALE(2); // divide by 8
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/* Start the timer */
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LPTMR0->CSR |= LPTMR_CSR_TEN_MASK;
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led = 0;
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while (true) {
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wait(1);
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led = 1;
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printf("%d\n", ticks);
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wait(1);
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led = 0;
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printf("%d\n", ticks);
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}
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}
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