#include <stdint.h> #include <avr/io.h> #include <avr/interrupt.h> #include <avr/pgmspace.h> #include "led.h" #include "sleep_led.h" #ifndef SLEEP_LED_TIMER # define SLEEP_LED_TIMER 1 #endif #if SLEEP_LED_TIMER == 1 # define TCCRxB TCCR1B # define TIMERx_COMPA_vect TIMER1_COMPA_vect # if defined(__AVR_ATmega32A__) // This MCU has only one TIMSK register # define TIMSKx TIMSK # else # define TIMSKx TIMSK1 # endif # define OCIExA OCIE1A # define OCRxx OCR1A #elif SLEEP_LED_TIMER == 3 # define TCCRxB TCCR3B # define TIMERx_COMPA_vect TIMER3_COMPA_vect # define TIMSKx TIMSK3 # define OCIExA OCIE3A # define OCRxx OCR3A #else error("Invalid SLEEP_LED_TIMER config") #endif /* Software PWM * ______ ______ __ * | ON |___OFF___| ON |___OFF___| .... * |<-------------->|<-------------->|<- .... * PWM period PWM period * * 256 interrupts/period[resolution] * 64 periods/second[frequency] * 256*64 interrupts/second * F_CPU/(256*64) clocks/interrupt */ #define SLEEP_LED_TIMER_TOP F_CPU / (256 * 64) /** \brief Sleep LED initialization * * FIXME: needs doc */ void sleep_led_init(void) { /* Timer1 setup */ /* CTC mode */ TCCRxB |= _BV(WGM12); /* Clock selelct: clk/1 */ TCCRxB |= _BV(CS10); /* Set TOP value */ uint8_t sreg = SREG; cli(); OCRxx = SLEEP_LED_TIMER_TOP; SREG = sreg; } /** \brief Sleep LED enable * * FIXME: needs doc */ void sleep_led_enable(void) { /* Enable Compare Match Interrupt */ TIMSKx |= _BV(OCIExA); } /** \brief Sleep LED disable * * FIXME: needs doc */ void sleep_led_disable(void) { /* Disable Compare Match Interrupt */ TIMSKx &= ~_BV(OCIExA); } /** \brief Sleep LED toggle * * FIXME: needs doc */ void sleep_led_toggle(void) { /* Disable Compare Match Interrupt */ TIMSKx ^= _BV(OCIExA); } /** \brief Breathing Sleep LED brighness(PWM On period) table * * (64[steps] * 4[duration]) / 64[PWM periods/s] = 4 second breath cycle * * https://www.wolframalpha.com/input/?i=sin%28x%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] PROGMEM = {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}; ISR(TIMERx_COMPA_vect) { /* Software PWM * timer:1111 1111 1111 1111 * \_____/\/ \_______/____ count(0-255) * \ \______________ duration of step(4) * \__________________ index of step table(0-63) */ 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 == pgm_read_byte(&breathing_table[timer.pwm.index])) { led_set(0); } }