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- #include "ch.h"
- #include "hal.h"
-
- #include "led.h"
- #include "sleep_led.h"
-
- #if defined(KL2x) || defined(K20x) /* platform selection: familiar Kinetis chips */
- /* All right, we go the "software" way: LP timer, toggle LED in interrupt.
- * Based on hasu's code for AVRs.
- */
-
- /* Breathing Sleep LED brighness(PWM On period) table
- * (64[steps] * 4[duration]) / 64[PWM periods/s] = 4 second breath cycle
- *
- * http://www.wolframalpha.com/input/?i=%28sin%28+x%2F64*pi%29**8+*+255%2C+x%3D0+to+63
- * (0..63).each {|x| p ((sin(x/64.0*PI)**8)*255).to_i }
- */
- static const uint8_t breathing_table[64] = {
- 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 2, 4, 6, 10,
- 15, 23, 32, 44, 58, 74, 93, 113, 135, 157, 179, 199, 218, 233, 245, 252,
- 255, 252, 245, 233, 218, 199, 179, 157, 135, 113, 93, 74, 58, 44, 32, 23,
- 15, 10, 6, 4, 2, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0
- };
-
- /* Low Power Timer interrupt handler */
- OSAL_IRQ_HANDLER(KINETIS_LPTMR0_IRQ_VECTOR) {
- OSAL_IRQ_PROLOGUE();
-
- /* Software PWM
- * timer:1111 1111 1111 1111
- * \_____/\/ \_______/____ count(0-255)
- * \ \______________ duration of step(4)
- * \__________________ index of step table(0-63)
- */
-
- // this works for cca 65536 irqs/sec
- static union {
- uint16_t row;
- struct {
- uint8_t count:8;
- uint8_t duration:2;
- uint8_t index:6;
- } pwm;
- } timer = { .row = 0 };
-
- timer.row++;
-
- // LED on
- if (timer.pwm.count == 0) {
- led_set(1<<USB_LED_CAPS_LOCK);
- }
- // LED off
- if (timer.pwm.count == breathing_table[timer.pwm.index]) {
- led_set(0);
- }
-
- /* Reset the counter */
- LPTMR0->CSR |= LPTMRx_CSR_TCF;
-
- OSAL_IRQ_EPILOGUE();
- }
-
- /* LPTMR clock options */
- #define LPTMR_CLOCK_MCGIRCLK 0 /* 4MHz clock */
- #define LPTMR_CLOCK_LPO 1 /* 1kHz clock */
- #define LPTMR_CLOCK_ERCLK32K 2 /* external 32kHz crystal */
- #define LPTMR_CLOCK_OSCERCLK 3 /* output from OSC */
-
- /* Work around inconsistencies in Freescale naming */
- #if !defined(SIM_SCGC5_LPTMR)
- #define SIM_SCGC5_LPTMR SIM_SCGC5_LPTIMER
- #endif
-
- /* Initialise the timer */
- void sleep_led_init(void) {
- /* Make sure the clock to the LPTMR is enabled */
- SIM->SCGC5 |= SIM_SCGC5_LPTMR;
- /* Reset LPTMR settings */
- LPTMR0->CSR = 0;
- /* Set the compare value */
- LPTMR0->CMR = 0; // trigger on counter value (i.e. every time)
-
- /* Set up clock source and prescaler */
- /* Software PWM
- * ______ ______ __
- * | ON |___OFF___| ON |___OFF___| ....
- * |<-------------->|<-------------->|<- ....
- * PWM period PWM period
- *
- * R interrupts/period[resolution]
- * F periods/second[frequency]
- * R * F interrupts/second
- */
-
- /* === OPTION 1 === */
- #if 0
- // 1kHz LPO
- // No prescaler => 1024 irqs/sec
- // Note: this is too slow for a smooth breathe
- LPTMR0->PSR = LPTMRx_PSR_PCS(LPTMR_CLOCK_LPO)|LPTMRx_PSR_PBYP;
- #endif /* OPTION 1 */
-
- /* === OPTION 2 === */
- #if 1
- // nMHz IRC (n=4 on KL25Z, KL26Z and K20x; n=2 or 8 on KL27Z)
- MCG->C2 |= MCG_C2_IRCS; // fast (4MHz) internal ref clock
- #if defined(KL27) // divide the 8MHz IRC by 2, to have the same MCGIRCLK speed as others
- MCG->MC |= MCG_MC_LIRC_DIV2_DIV2;
- #endif /* KL27 */
- MCG->C1 |= MCG_C1_IRCLKEN; // enable internal ref clock
- // to work in stop mode, also MCG_C1_IREFSTEN
- // Divide 4MHz by 2^N (N=6) => 62500 irqs/sec =>
- // => approx F=61, R=256, duration = 4
- LPTMR0->PSR = LPTMRx_PSR_PCS(LPTMR_CLOCK_MCGIRCLK)|LPTMRx_PSR_PRESCALE(6);
- #endif /* OPTION 2 */
-
- /* === OPTION 3 === */
- #if 0
- // OSC output (external crystal), usually 8MHz or 16MHz
- OSC0->CR |= OSC_CR_ERCLKEN; // enable ext ref clock
- // to work in stop mode, also OSC_CR_EREFSTEN
- // Divide by 2^N
- LPTMR0->PSR = LPTMRx_PSR_PCS(LPTMR_CLOCK_OSCERCLK)|LPTMRx_PSR_PRESCALE(7);
- #endif /* OPTION 3 */
- /* === END OPTIONS === */
-
- /* Interrupt on TCF set (compare flag) */
- nvicEnableVector(LPTMR0_IRQn, 2); // vector, priority
- LPTMR0->CSR |= LPTMRx_CSR_TIE;
- }
-
- void sleep_led_enable(void) {
- /* Enable the timer */
- LPTMR0->CSR |= LPTMRx_CSR_TEN;
- }
-
- void sleep_led_disable(void) {
- /* Disable the timer */
- LPTMR0->CSR &= ~LPTMRx_CSR_TEN;
- }
-
- void sleep_led_toggle(void) {
- /* Toggle the timer */
- LPTMR0->CSR ^= LPTMRx_CSR_TEN;
- }
-
- #else /* platform selection: not on familiar Kinetis chips */
-
- void sleep_led_init(void) {
- }
-
- void sleep_led_enable(void) {
- led_set(1<<USB_LED_CAPS_LOCK);
- }
-
- void sleep_led_disable(void) {
- led_set(0);
- }
-
- void sleep_led_toggle(void) {
- // not implemented
- }
-
- #endif /* platform selection */
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